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OXY-ACETYLENE WELDING
PRACTICE
A PRACTICAL PRESENTATION OF THE MODERN PROCESSES OF
WELDING, CUTTING, AND LEAD BURNING, WITH SPECIAL
ATTENTION TO WELDING TECHNIQUE FOR STEEL,
CAST IRON, ALUMINUM, COPPER, AND BRASS
BY
ROBERT J. KEHL, M.E.
M
CONSULTING MECHANICAL ENGINEER, CHICAGO
AMERICAN SOCIETY OF MECHANICAL ENGINEERS
ASSOCIATE, AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS
ILLUSTRATED
AMERICAN TECHNICAL SOCIETY
CHICAGO
1918
COPYRIGHT, 1917, BY
AMERICAN TECHNICAL SOCIETY
COPYRIGHTED IN GREAT BRITAIN
ALL RIGHTS RESERVED
- •v1$0"H,
INTRODUCTION
HIGH-TEMPERATURE flames, such as the oxy-hydrogen
flame, were known for many years, but the oxy-acetylene flame
was first used experimentally in 1901 by Fouche and Picard. The
same experimenters also developed the first welding blowpipes, used
industrially in 1903, and started the developments in oxy-acetylene
welding which were destined to become so important in the modern
manufacturing and repair fields. Cutting by means of oxygen
was first made commercially possible in 1905 by Jottrand, who took
out his basic patent in that year.
<I Many difficulties were encountered in the early development,
owing to imperfect knowledge of the character of the flame and of
the technique of the method of application, but notwithstanding
these difficulties, the oxy-acetylene welding and cutting processes
have developed wonderfully, especially during the last ten years,
during which time they have replaced old methods and have made
possible operations which hitherto could not be accomplished.
The discovery of liquid air greatly decreased the cost of oxygen,
and the increase in the number of oxygen supply points throughout
the country has removed the last obstacle to the rapid advance of
the art. Everywhere manufacturers are very willing to supplant
their old methods by the oxy-acetylene process.
<I Their rapid increase in the number of plants using the process
has produced an active demand for skilled operators, a demand which
unfortunately has been always much greater than the supply. How-
ever, now that the apparatus on the market has become standardized
and our knowledge of good oxy-acetylene practice has reached a
point where methods can be carefully outlined, the publishers of this
little volume feel that an authoritative article on this subject will be
appreciated by the many persons interested in the welding field. The
material has been written for the welding operator as well as for the
superintendent and manager. The examples have been taken from
the automobile industry because in that field almost every phase or
class of welding is covered, and while the instructions and data deal
with automobile welding in particular, the repairman and manu-
facturer will find no difficulty in applying this information to their
own particular needs. The publishers will be very glad to give
special information to any reader, either through their own experts
or through the help of the author himself.
.
371608
CONTENTS
WELDING PROCESSES
PAGE
Oxy-acetylene process 3
Advantages 3
Gases ." 3
Generators 5
Welding blowpipes 7
Oxy-acetylene flame 8
Expansion and contraction 8
Preparation of work 8
Welding rod : 8
Flux 9
Strength of weld 9
Oxy-acetylene cutting 10
Electric processes 11
Methods 11
Spot-welder 11
Arc welder . . 12
TECHNIQUE OF OXY-ACETYLENE WELDING
Simple welding job 14
Apparatus required 14
Preparing the metal 14
Connecting the apparatus 14
Welding 15
Operation and care of welding apparatus 16
Necessity for care 16
Necessary welding apparatus 16
Welding blowpipe 16
Regulators 19
Hose 21
Instructions for connecting apparatus 22
i How to light blowpipe 23
How to shut off blowpipe 23
Back-firing 24
Character of flame 24
Position of blowpipe 27
Position of welding rod 29
Haste fatal to good welding 31
How to weld up a hole 31
Overhead and vertical welding 31
Beginning a long weld 31
Defects in welds. . 32
CONTENTS
PAGE
Welding different metals 34
Properties of metals 34
Expansion and contraction 36
Handling simple case of expansion and contraction 37
Handling complex case of expansion and contraction 39
Pre-heating 40
Steel welding 43
Cast-iron welding 59
Malleable-iron welding 67
Aluminum welding 68
Copper welding 72
Brass and bronze welding 74
MISCELLANEOUS OXY-ACETYLENE PROCESSES
Cutting 76
Principle of cutting with oxygen 77
Cutting blowpipe 78
Regulators 79
Care of apparatus 79
Instructions for connecting apparatus 79
How to light blowpipe 79
To shut off blowpipe 80
Back-firing 80
Notes on cutting 81
Lead burning : . . . 81
Different methods 81
Lead-burning apparatus 83
Operation of lead-burning apparatus 83
Lead-burning process 84
Carbon removing by use of oxygen 85
Old process of removing carbon 85
Carbon-removing apparatus 86
Burning out carbon 86
EXAMPLES OF AUTOMOBILE REPAIR
Pressed-steel parts 87
Frames 87
Bodies and fenders 89
Springs 92
Shafts and axles 93
Axle housings 94
Manifolds 94
Engine cylinders 95
Crankcases and transmission cases 97
COSTS
Measuring oxygen consumption 99
Measuring acetylene consumption 102
OXY- ACETYLENE WELDING
PRACTICE
INTRODUCTION
Welding Field. The welding process is undoubtedly one of the
greatest contributors to the efficient and economical manufacture of
the modern automobile. It has made possible higher standards of
body design and may be given almost exclusive credit for the light
weight and great strength of the present-day motor car, producing
stronger and better working parts through the use of pressed steel
instead of the heavy castings or riveted parts, such as axle housings,
Fig. 1, and manifolds, tanks, bodies, etc., Fig. 2.
In the field of automobile repair it is rapidly assuming an equally
important place, affording a quick and inexpensive means of perma-
nent repair to parts no longer obtainable from the supply house or
manufacturer and permitting the building up of weak parts or the
altering of the chassis, as may be required. This great adaptability
of the welding unit has made it an essential part of the equipment of
every efficiently managed repair shop.
WELDING PROCESSES
Old and New Methods. The old systems — blacksmith, or forge,
welding, and brazing — are now seldom used in automobile work.
In fact, most blacksmiths have equipped themselves to do welding in
the modern way, using it almost exclusively for their repair work
because it is cheaper, simpler, more efficient, and can be used on
materials which could not be welded by means of the old-style
methods. The modern systems of welding include the flame and
electric processes. Because it is almost universally used in repair
shops, the flame process and the apparatus required in its use will
be discussed first. Several flame-welding processes have, from time
to time, been introduced, all utilizing oxygen in combination with
some fuel gas, such as acetylene, hydrogen, city gas, natural gas,
liquid gas, Blau gas, carbo-hydrogen, thermaline, etc. Many enthu-
OXY-ACKTYLENE WELDING
Fig. 1. Oxy-Acetylene Welding in Manufacture of Rear Axle Housings
.Fig. 2. Oxy-Acetylene Welding in Manufacture of Automobile Bodies
OXY-ACETYLENE WELDING 3
siastic claims of superiority have been made for each of these combi-
nations by their advocates.
OXY=ACETYLENE PROCESS
Advantages. The easy control and intensity of the heat devel-
oped by the oxy-acetylene flame (approximately 6300° F.) and the
adequate supplies of carbide and dissolved acetylene which are
maintained in every industrial center in the United States have
proved the greater desirability, economy, and efficiency of the oxy-
acetylene process.
Another factor which has contributed largely to the popularity
of the oxy-acetylene process is the comparatively inexpensive appara-
tus required and the low cost of its operation. Its speed, portability,
and the ease with which its method of operation may be learned by
any intelligent workman make it especially well fitted to the need of
the automobile repair shop. Very seldom is any extensive disman-
tling of parts necessary in making an oxy-acetylene repair and, for this
reason, it simplifies greatly the work of the repair man.
Gases. As is generally known, two gases are used in the oxy-
acetylene process — oxygen and acetylene.
Oxygen. Oxygen is manufactured from air by liquefaction or
from water by electrolysis. The former method is by far the greatest
source of supply, furnishing practically all the oxygen used in this
country and abroad. Oxygen made by the liquid-air process can
contain only an impurity such as nitrogen, which cannot possibly do
any harm. On the other hand, oxygen made by the electrolytic
method contains some hydrogen, which will render it dangerous to
handle if more than two per cent is present.
Because of the very high cost of an oxygen plant and the ease
with which an adequate supply of compressed gas may be obtained
from manufacturers' supply stations, it has been found impractical
for even the largest consumers to attempt the manufacture of their
own oxygen.
Almost everybody is familiar with the appearance of the oxygen
cylinder, shown at the right in Fig. 3, which plays so important a
part in present-day manufacturing. These steel cylinders contain
100 or 200 cubic feet of gas compressed to a pressure of 1800 pounds
per square inch. They are furnished to the consumer without charge,
OXY-ACETYLENE WELDING
the customer paying only for the oxygen and returning the cylinder to
the manufacturer when the gas has been exhausted.
Acetylene. The acetylene may be obtained in cylinders, shown at
the left in Fig. 3, containing 100 or 300 cubic feet, or, where large
quantities are re-
quired, it is generated
on the premises.
Though frequently re-
ferred to as com-
pressed, the acetylene
in cylinders is really
not compressed, but
is dissolved in a sol-
vent which has the
property of absorbing
many times its own
volume of acetylene as
pressure is applied.
This liquid in which
the gas is dissolved in
no way affects the flow
of gas except when the
acetylene is drawn off
from the cylinder at
too rapid a rate. Ex-
perience has proved
that when the gas is
used at a rate greater
than one-seventh the
capacity of the cylin-
der per hour, the
solvent is very likely
to travel with the
acetylene, lowering the
temperature of the flame and thus hindering the work. To overcome
this difficulty, where it is necessary to supply gas at a greater rate,
several cylinders may be coupled to a manifold, or header, so that the
total capacity is at least seven times their hourly discharge.
Fig. 3. Welding Unit for Use with Acetylene in Cylinders,
Mounted on Emergency Truck
Courtesy of Oxwdd Acetylene Company, Chicago, Illinois
OXY-ACETYLENE WELDING 5
Generators. By means of the acetylene generator it is possible
to produce pure acetylene at less than half the cost of dissolved acety-
lene, so that if any considerable work is to be done a generator
will pay for itself within a few months or a year. In these generators
small quantities of calcium carbide are automatically fed into a large
Fig. 4. Low-Pressure Acetylene Generator
Courtesy of Oxweld Acetylene Company, Chicago, Illinois
quantity of water, producing the gas at just the rate required by the
work in hand.
There are two recognized systems of generating acetylene —
the low-pressure system and the pressure system.
Low-Pressure Generator. This type of generator, Fig. 4, delivers
acetylene to the blowpipe under a pressure of less than one pound.
This system has the advantage of maintaining at all times an abso-
6
OXY-ACETYLENE WELDING
lutely constant pressure, which is an essential requirement. The
carbide feed is controlled by the rise and fall of the gas bell, in which
the pressure is always the same, without the use of any pressure-
regulating device.
Pressure Generator. The pressure generator, Fig. 5, delivers
acetylene at a pressure of more than one pound. The carbide feed is
controlled by the pressure in the generator. As the acetylene is
drawn off and the pressure decreases, carbide is fed into the water;
Fig. 5. Portable Pressure Acetylene Generator
Courtesy of Oxweld Acetylene Company, Chicago, Illinois
the generation of gas increases the pressure and the feeding stops.
In order to compensate for this pressure variation, a pressure-dia-
phragm regulator, or reducer, is necessary so that the acetylene may
be supplied to the blowpipe at a constant pressure.
The low-pressure generator furnishes the most satisfactory
service under average conditions, though where portability is essen-
tial, pressure generators of compact construction may be obtained to
meet this need.
OXY-ACETYLENE WELDING 7
Welding Blowpipes. There are two types of oxy-acetylene
welding blowpipes, namely, the low-pressure, or injector type and
the equal-pressure type.
Fig. 6. Oxy-Acetylene Welding Blowpipe
Courtesy of Oxwdd Acetylene Company, Chicago, Illinois
Injector Blowpipe. In the injector type, Fig. 6, the acetylene is
delivered to the blowpipe at a pressure of only a few ounces. The
oxygen at a higher pressure passes through the injector, Fig. 7, and
expands rapidly into the mixing chamber. This rapid expansion
and high velocity of the oxygen form a suction and draw in the acety-
lene at a constant ratio. A slight variation in pressure of either
Fig. 7. Section of Injector-Type Blowpipe
the oxygen or acetylene is automatically taken care of by the injector,
so that a neutral flame is maintained at all times.
Pressure Blowpipe. In this blowpipe the acetylene is used at
almost the same pressure as the oxygen. The oxygen enters the
mixing chamber at the rear and the acetylene through a couple of
holes at the side.
Fig. 8. Section of Pressure-Type Blowpipe
In the injector blowpipe the rapid expansion into the tapered
mixing chamber sets up a whirling action and produces an intimate
mixture of the oxygen and acetylene so that a ratio of 1.05 parts
oxygen to 1,00 part acetylene is obtained, which is almost the theo-
8 OXY-ACETYLENE WELDING
retical or perfect ratio of 1 .00 to 1 .00. In the pressure blowpipe there
is no means of obtaining such an intimate mixture of the gases in the
mixing chamber, Fig. 8, which in most cases is not tapered, and con-
sequently about the best ratio obtainable is 1.14 to 1.00. This larger
amount of oxygen is, of course, wasted and, besides, tends to produce
an oxidized weld. It is the surface oxidation, or burning, of the
molten metal that leads some operators to believe that they are
welding fast, while in reality they are only burning the surface and are
not fusing the metal underneath.
Oxy=Acetylene Flame. The oxy-acetylene flame is the hottest
flame obtainable. Its temperature of 6300° F. is 2000 degrees above
that of any of the other flames. This high temperature allows the
work to be done quickly and with only a very slight loss of heat due
to conduction and radiation.
There are three phases of the oxy-acetylene flame, Fig. 18,
namely, the neutral, or welding, flame; the carbonizing, or reducing,
flame; and the oxidizing flame. Each of these has its characteristic
appearance and it takes only a little practice to instantly recognize
them. The appearance of these will be taken up later under "Flame
Regulation", page 25.
Expansion and Contraction. These natural changes of the work,
due to the heat of the welding, are taken care of in the case of rolled or
forged materials by proper spacing of the edges or by holding the work
in suitable jigs and, in the case of castings, by proper pre-heating and
cooling. The most satisfactory methods of handling this feature will
be taken up under the instructions for welding various materials.
Preparation of the Work. This is a very important feature and
should receive the operator's best thought and effort. A fair amount
of reasoning and planning on the part of the operator before he
attempts a job will save considerable time and keep the cost of the
welding low. The operator should figure out several ways and means
of handling the particular task at hand, and should then select the
best. This applies especially to castings, such as crankcases and
cylinders, which may be welded perfectly if the operator uses good
judgment but which will be ruined if he does not.
Welding Rod. Thin plates may be welded by bringing the edges
into contact and fusing them together. For heavier work, the edges
are beveled to form a groove, and a filling material, or "welding-
OXY-ACETYLENE WELDING 9
rod", is fused into the groove. In most cases a material similar to
the work being welded is used. The operator may build up the weld
by means of the welding rod so that the section at the weld is greater
than the section before welding, thus insuring a strength even greater
than the rest of the piece.
Flux. A suitable flux is used in cast iron, aluminum, brass,
•copper, etc., welding to dissolve any impurities and to give a film,
or protecting coating, to the fused material to prevent oxidation.
Both the welding rod and the flux used are extremely Important
factors in the welding and should be obtained from a reliable manu-
facturer who supplies only materials that are tested and analyzed to
determine their purity and suitability for the work.
Strength of Weld. With proper equipment and suitable rods
and fluxes, the strength of the weld will depend mainly upon the skill
Fig. 9. Oxy-Acetylene Cutting Blowpipe
Courtesy of Oxweld Acetylene Company, Chicago, Illinois
and care of the operator. An operator who has had considerable
experience and who is careful with his work should be able to obtain
as high as 95 per cent the strength of the original material, although 85
per cent may be taken as a safe lower limit for the average good welder.
Working and Hammering. If the weld is hammered when at
the proper temperature, its strength will be increased, in the case of
welds in steel, by making the grain of the material finer.
Experience of Operator. Poor work due to carelessness or
inexperience of the operator, poorly designed and cheaply constructed
apparatus that is not capable of handling the work, may be held
responsible for such failures as may occur in the oxy-acetylene process.
The handling of the process is not difficult and, therefore, some
operators undertake difficult jobs before they are sufficiently capable
or experienced. When such a job fails, it is but natural that both the
10
OXY-ACETYLENE WELDING
customer and the operator should blame the process rather than the
way in which the work was handled. Time may be very profitably
spent in practice on scrap material before undertaking work on mate-
rials with which the operator is unfamiliar. By thus laying the
foundation for a satisfactory result, the operator may quickly develop
Fig. 10. Electric Spot- Welding Machine
Courtesy of Thomson Spot Welder Company, Cincinnati, Ohio
his skill to the point which will bring him the confidence and patron-
age of a constantly increasing number of customers.
Oxy=Acetylene Cutting. Cutting by the oxy-acetylene process
is done by means of a separate blowpipe, Fig. 9, quite different in
construction from that used for welding. A more detailed description
of the cutting process is given on page 77.
OXY-ACETYLENE WELDING
11
ELECTRIC PROCESSES
Methods. For a number of years electric welding was used as a
, laboratory experiment, but recently the process has been more fully
/ developed. Two distinct methods are utilized: one, the electric-
resistance welder, or spot- welder, Fig. 10; and the other, the electric-
arc welding machine, Fig. 11.
Spot=Welder. The electric-resistance welding process provides
for the passage of a heavy current through the joint between the
pieces to be welded, allowing the resistance of the bad contact to heat
them locally until they are soft enough to stick together; squeezing
Fig. 11. Portable Arc-Welding Outfit
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey
the pieces while soft will then cause them to adhere. This process is
used mostly in making light automobile parts, such as mud guards,
bonnets, etc., rather than for repair. It is also used to some extent
instead of small rivets in light sheet-metal work and for spotting, or
tacking, small parts together preparatory to welding them with the
oxy-acetylene flame.
12
OXY-ACETYLENE WELDING
Arc Welder. In order to do welding with the electric arc, after
suitable equipment has been provided, it is necessary to first connect
the work to the positive side of the power-supply circuit and the
welding electrode to the negative side of the circuit by means of wires
or cables, with the regulating devices in circuit to control the amouut
of current flowing. tlie negative electrode is then placed lightly in
contact with the wdrk and quickly withdrawn to make the circuit
Fig. 12. Operator Using Metallic Electrode
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey
and draw the arc, thus providing the high temperature required for
welding.
Electric-arc welding usually consists in using the heat of the arc
to fuse, or melt, the filling material into the place to be filled, although
the article worked upon may be melted down sufficiently to fill the
space if it is large enough at the point to be welded.
Two methods, or processes, using the arc for welding, are in
commercial use, these being the metallic and the graphite, or carbon,
processes.
OXY-ACETYLENE WELDING
13
Metallic Electrode. The metallic welding process consists in using
a piece of wire of the proper kind as the negative electrode of the arc
and fusing it into place, drop by drop, Fig. 12.
Graphite Electrode. The graphite process consists in using a piece
of graphite, or carbon, as the negative electrode and fusing a piece of
metal into place by the heat of the arc.
Apparatus. It is possible, though not practical, to do electric-
arc welding, having nothing but a source of primary current, and some
SEKIES RELAY
WORK 4-
Fig. 13. Wiring Diagram for C & C Welding System
means for regulating the amount of current flowing, but the use of
resistance only as a means of regulating the amount of current flow is so
wasteful that other apparatus must be used for the sake of economy.
It is well known among electrical men that a motor-generator set
gives the best regulation of voltage, therefore, the leading arc-welding
outfits in use today consist of a motor-generator set with suitable
rheostats, resistances, circuit-breakers, fuses, indicating instruments,
and switches for controlling the motor-generator and welding cir-
cuits, Fig. 13.
14 OXY-ACETYLENE WELDING
From the foregoing description, it will be surmised that an electric-
arc welding equipment will be too expensive in initial cost for the
average auto repair shop. However, it finds a useful field in the
welding of very heavy work where there is sufficient volume of it to
justify the investment.
TECHNIQUE OF OXY-ACETYLENE WELDING
SIMPLE WELDING JOB
Apparatus Required. The material in the following paragraphs
must not be considered as instructions for welding but merely as a
brief discussion of the various steps in making a simple weld. Com-
plete instructions for connecting and operating the equipment are
given in detail later. In general, the following equipment is needed
for every welding job, no matter how small:
(a) A welding blowpipe
(b) A supply of oxygen
(c) An oxygen regulator
(d) A supply of acetylene
(e) An acetylene regulator
(f) Hose to connect blowpipe to oxygen and acetylene supplies
Preparing the Metal. First, the edges of the two pieces of metal
to be welded are chamfered or beveled, so that when they are placed
together the two beveled edges form a V, the width of the V being
about equal to the thickness of the metal.
Next, the two pieces are placed together on a flat surface of fire
brick, or other nonconductor of heat, so that the edges just touch at
the bottom of the groove. This gives the line of the weld. The two
pieces are then ready to be welded as soon as the apparatus is con-
nected.
Connecting the Apparatus. To connect the apparatus, the
following steps should be taken:
(1) The oxygen regulator is connected to the oxygen cylinder.
(2) The acetylene regulator is connected to the acetylene cylinder.
(3) The one hose is connected to the oxygen regulator and to the
blowpipe.
(4) The other hose is connected to the acetylene regulator and to the
blowpipe.
OXY-ACETYLENE WELDING 15
(5) A welding head is selected and attached to the blowpipe.
(6) The oxygen and acetylene are turned on and the blowpipe is
lighted.
Welding. The operator is now ready to weld. He takes the
lighted blowpipe in his right hand, Fig. 14, and plays the flame upon
the beveled edges of the two pieces of metal to be welded. The
intense heat of the flame melts the edges and they flow together. As
Fig. 14. Simple Job of Welding
the edges flow together, the operator melts in new metal from a rod
which he holds in his left hand, so that the entire goove is filled up,
producing a perfect union or weld.
When the entire groove has been filled in this manner, the
operator turns out the blowpipe, and allows the metal to cool.
The foregoing is a brief outline of the steps taken by an operator
in performing a simple operation of welding two small pieces of steel.
We will now take up these different steps and will give more
specific and detailed descriptions of the welding apparatus and com-
plete instructions in its operation and use.
16 OXY-ACETYLENE WELDING
OPERATION AND CARE OF WELDING APPARATUS
Necessity for Care. It is proper that in the operation of the
welding apparatus we should lay stress upon the importance of careful
and orderly methods in the handling of such apparatus. It should
be borne in mind that the regulators and gages are sensitive measuring
devices, that in the blowpipe the orifices are carefully designed and
accurately machined to permit the passage of a definite quantity of
gas and, therefore, that rough usage and abuse will certainly decrease
their efficiency. It is not necessary in this place to give detailed
instructions for the operation and care of the various makes of appara-
tus, because these are invariably furnished by the manufacturers with
their equipment.
Because of the fact that dissolved acetylene is most generally
used in garages and small job shops, we will confine our explanations
to the use of apparatus with cylinder equipment. Owing to the
greater simplicity of handling, however, the operator will have no
difficulty in making use of generated acetylene when the opportunity
arises.
Necessary Welding Apparatus. A complete welding station,
Fig. 15, for use with acetylene dissolved in cylinders, consists of the
following apparatus:
Welding blowpipe G with set of welding heads
Oxygen welding regulator C with two gages
Acetylene regulator D with one or two gages
Adapter L for acetylene cylinder
Two lengths high-pressure hose E and F
Darkened spectacles, wrenches, hose clamps, etc.
Welding Blowpipe. The two types of welding blowpipes were
described on pages 7 and 8, and need no further explanation as to
the principles of operation. They are furnished by the manufacturers
in various lengths to take care of various classes of work, from short
light-weight blowpipes less than a foot long for light sheet-metal work
up to blowpipes several feet long, which allow the operator to stay
away from the intense heat as far as possible when working on heavy
jobs.
Welding Heads and Tips. About ten sizes of welding heads,
or tips, are supplied for use on different thicknesses of metal and vari-
ous classes of work, each giving its own special size flame. The
OXY-ACETYLENE WELDING
17
oxygen consumption of the various size heads ranges from about 4 to
70 cubic feet per hour. In some makes the heads are made of one
Fig. 15. Complete Welding Station
piece, while in others they consist of a brass or bronze body and a
copper tip, which can be easily and cheaply replaced when necessary.
Working Pressures. The necessary pressures of the gas that are
required by the different size welding heads are given by the manufac-
18
OXY-ACETYLENE WELDING
turers, and it is very important that the operator use only the pres-
sures recommended if he wishes to get the best economy and the
strongest weld possible. Some operators believe that by increasing
the pressure above that specified by the maker of the apparatus that
they are able to do the work more quickly and easily. This idea is
wrong, because when the pressure is increased, the larger volumes of
oxygen and acetylene cannot mix as well, so that oxide forms in the
weld and has to be removed. This takes more time and is very likely
to leave a slightly oxidized and weak weld.
If the welding head being used is not large enough, use a larger
size; never try to increase the ability of the smaller head by increasing
the pressure.
It is equally bad to use a pres-
sure that is too low. If this is done,
continual back-firing will result.
Care of Blowpipe. If the blow-
pipe is handled properly there will
be very little deterioration. It
should only be necessary to clean
the replaceable and working parts
and occasionally ream out the tips.
The tips should never be
reamed out with any instrument
other than a copper or brass wire
having a long taper. Care should
be taken that the orifices of the tips are not enlarged by reaming.
If they become enlarged, they may be closed slightly by placing a
conical swag over the end and tapping lightly with a hammer. The
end of the tip should then be dressed off square by means of an
extra fine file, and the orifice trued round by reaming with a twist
drill of the proper size.
The blowpipe may be cleaned by removing both the acetylene
and the oxygen hose and connecting the tip to the oxygen hose.
Fig. 16, and turning on the oxygen to a pressure of about 20 pounds
per square inch, having the acetylene needle valve open and the oxygen
needle valve closed, so as to drive any obstructions through the larger
acetylene passages of the blowpipe. Then close the acetylene valve
and open the oxygen valve to clean out the oxygen passages.
Fig. 16. Cleaning Blowpipe by Means of
Oxygen under Pressure
OXY-ACETYLENE WELDING
19
Regulators. There are various types of regulators on the
market today, but the most successful ones are very similar in design
and construction. The principal parts of a constant-pressure regu-
lator, Fig. 17, consist of the body proper, regulator valve, diaphragm,
pressure-adjusting spring, safety-relief valve, and gages.
The diaphragm may be either special reinforced rubber sheeting
or phosphor bronze. The former is preferred, because it is less likely
to crack, or split, is more readily replaced, and gives more sensitive
regulation because of its finer elastic properties.
Fig. 17. Section of Pressure Regulator
Courtesy of Oxweld Acetylene Company, Chicago, Illinois
Operation of the Regulator. Gas passes from the cylinder valve
through the passageway to the regulator valve. The pressure over-
comes the tension of the inner spring and moves the sleeve-piece
toward the back of the regulator, opening the valve. This allows gas
to pass into the diaphragm chamber and out of the regulator by way
of the hose connection. As the pressure in the diaphragm chamber
increases, the tension of the pressure-adjusting spring is overcome,
the diaphragm deflects, the sleeve-piece moves forward, and the valve
20 OXY-ACETYLENE WELDING
closes partly or all the way. Then, as gas passes out of the regulator
and the pressure in the diaphragm chamber decreases, the tension
of the pressure-adjusting spring and the pressure of the gas entering
the regulator move the sleeve-piece backward, admitting more oxygen
to the regulator. The pressure in the diaphragm chamber builds up
as before, the diaphragm deflects, the sleeve-piece moves outward,
and the valve closes.
Oxygen Welding Regulator. This is an automatic regulator
which is especially designed for welding operations. It is connected
to the oxygen cylinder and is designed to deliver oxygen to the blow-
pipe at any uniform pressure at which the regulator is set. To do
successful welding, the oxygen regulator must be as nearly perfect as
it is possible to 'construct it. This device is required to reduce a
pressure which may be as high as 1800 pounds per square inch in
the cylinder and which is constantly varying, down to a pressure
from 10 to 30 pounds per square inch; at the same time the regulator
must keep the lower pressure constant.
Oxygen regulators are usually equipped with two gages. The
high-pressure gage shows the pressure of the gas in the cylinder and
may be used to determine the amount of oxygen in the cylinder (see
under Measuring Oxygen, page 99). The low-pressure gage shows
the operating pressure at which the oxygen is being supplied to the
blowpipe.
Acetylene Regulator. The acetylene regulator is used with
acetylene supplied in cylinders. It is connected to the acetylene
cylinder adapter, and this to the acetylene cylinder. The acetylene
regulator is designed to deliver acetylene at a uniform pressure, as
needed by the blowpipe.
Acetylene regulators are usually equipped with a large gage that
shows the pressure in the cylinder, but which cannot be used to
accurately determine the contents of the cylinder (see Measuring
Acetylene, page 102) . A small gage is not necessary with the low-
pressure, or injector, blowpipe, because the acetylene pressure required
by this type of blowpipe is very low — only a few ounces. With the
pressure blowpipe, however, a small gage is necessary, because it is
important to know that the acetylene pressure, which ranges from 2
to 13 pounds per square inch, is supplied to the blowpipe at the
required pressure for the tip used.
OXY-ACETYLENE WELDING 21
Care of Regulators. Never drop or jar a regulator. Do not use oil,
grease, or any organic material for lubrication in connection with regu-
lator. If it becomes necessary to lubricate the pressure-adjusting
screw, or to repack a needle valve, make use of a little glycerine —
nothing else.
Do not allow dust to enter the regulator. Always insert the
dust plug when the regulator is not in use. These are supplied with
most regulators and are intended to keep dust out of the regulator
when it is not in use and to protect the union nipple at the back.
Do not change the regulator from one cylinder to another without
releasing the pressure-adjusting screw. The diaphragm is liable to be
ruptured if there is tension on it when the sudden rush of gas takes
place as the cylinder valve is opened.
Do not attempt to repair, adjust, or change the internal mechan-
ism of the regulator, other than replacing the diaphragm and resurfac-
ing or replacing the valve seat. Send it to the manufacturer for
repairs.
Do not replace diaphragms or valve seats with any material
other than that supplied by the manufacturer for this purpose.
Hose. The best hose that it is possible to obtain should be used,
because it is really the most economical in the end, although it might
cost more at the beginning. A good grade of two-ply hose will be
found to be flexible, light weight, easy to handle, and, at the same
time, will not kink easily nor be permanently flattened if heavy
objects happen to accidentally fall on it. In selecting a hose, the
welder should see that he gets a hose that has a finished inside surface,
so that small particles of rubber and dust will not flake off and be
blown into and clog the blowpipe or welding head.
It is best to use different colored hose for the oxygen than for
the acetylene to prevent errors in connecting and to avoid any pos-
sible danger from interchanging.
Care of Hose. Both the acetylene and the oxygen hose should be
blown out occasionally so that dirt and dust will not be carried into
the blowpipe. This can be done by removing the hose from the
blowpipe, connecting each in turn to the oxygen regulator, and
allowing oxygen of about 20 pounds per square inch to blow through
it. Examine the hose, from time to time, for leaks by immersing in
water when under pressure.
22 OXY-ACETYLENE WELDING
INSTRUCTIONS FOR CONNECTING APPARATUS
Preliminary Operations. The following directions are given
as a starting point for beginners in the operation of welding equipment.
The letters given refer to the labeled parts in Fig. 15, page 17.
1. First open the oxygen cylinder valve B for a moment to
blow out any dirt or dust which may have collected in the valve, so
that it cannot enter the oxygen regulator when it is attached to the
cylinder.
2. Remove the regulator dust plug and attach the oxygen
regulator C to the oxygen cylinder A.
3. Connect the oxygen hose E to the oxygen regulator and to
the oxygen hose connection on the blowpipe G. The hose connec-
tions are usually readily distinguished by markings on the needle
valves.
4. Release the pressure-adjusting screw on the oxygen regulator
by turning to the left until it is perfectly free.
Do not open the valve on the oxygen cylinder until positive that
the adjusting screw on the regulator is fully released. The diaphragm
may be ruptured and the regulator put out of commission.
5. Slowly open the oxygen cylinder valve B as far as it will go.
Not part way.
Do not leave the valve on the oxygen cylinder only part way open.
This valve seats when fully opened or closed, but is likely to leak when
open only part way.
Do not handle the regulator with greasy hands nor allow any oil,
soap, or organic matter to come in contact with any part of the regu-
lator or cylinder valve. Oxygen under high pressure coming in con-
tact with these substances is dangerous.
6. Wipe out the acetylene cylinder valve to remove any dirt
or dust which may have collected in the valve, so that it cannot enter
the acetylene regulator when it is attached to the cylinder.
7. Attach the adapter L to the acetylene cylinder K.
8. Remove the regulator dust plug and attach the acetylene
regulator D to the adapter.
9. Connect the acetylene hose F to the acetylene regulator and
to the acetylene hose connection on the blowpipe G.
10. Release the pressure-adjusting screw on the acetylene
regulator by turning to the left until it is perfectly free.
OXY-ACETYLENE WELDING 23
11. Open the acetylene cylinder valve about three full turns by
means of the wrench J.
12. Select the welding head of the size suitable for the work in
hand. Screw the welding head down firmly, but not too tightly, into
the head of the blowpipe with the wrench provided for that purpose.
Starting the Work
How to Light the Blowpipe. 1. Take the blowpipe in hand and
open the oxygen needle valve fully.
2. Turn the oxygen pressure-adjusting screw to the right until
the required pressure for the welding head being used shows on the
low-pressure gage. See the maker's chart for the correct pressure.
3. Close the oxygen needle valve.
4. Open the acetylene needle valve fully.
5. Turn the acetylene pressure-adjusting screw to the right until
a good jet of acetylene issues from the welding-head orifice. In the
case of pressure blowpipes, turn the screw until the required pressure
for the welding head being used shows on the low-pressure gage. (See
the maker's chart for the correct pressures).
6. Open the oxygen needle valve slightly and light the blowpipe
by means of the pyro-lighter that is usually furnished. ,
7. Open the oxygen needle valve fully.
NOTE : A back-fire might occur when turning on the oxygen if there is not
enough acetylene being supplied. If this occurs, increase the acetylene supply
by turning the acetylene pressure-adjusting screw farther to the right.
8. Adjust the acetylene pressure-adjusting screw to give a
slight excess of Acetylene to the flame.
9. Adjust the acetylene needle valve to give a neutral flame
(see under Flame Regulation, page 25) .
How to Shut Off the Blowpipe. In the case of the injector type
blowpipe, first close the acetylene needle valve, and then the oxygen
needle valve.
In the case of pressure blowpipes, first close the oxygen needle
valve, and then the acetylene needle valve.
When laying aside the blowpipe for a short time, the pressure-
adjusting screws on both regulators should be released by turning to
the left until free.
When work is suspended for any considerable time, the valves
on both cylinders should be closed.
24 OXY-ACETYLENE WELDING
Never light the blowpipe unless some oxygen is passing through it.
If the blowpipe is lighted, or burned, with only acetylene passing
through it, there will be a deposit of carbon made in the tip, which will
in time clog the orifice and interfere with the perfect operation of
the blowpipe.
Back=Firing. If the flame is not properly adjusted, or the tip
becomes clogged, the blowpipe may back-fire. When this occurs,
first close the acetylene needle valve quickly, then open it again fully
and relight the blowpipe. If the back-fire continues, close both the
acetylene and oxygen needle valves. Then relight the blowpipe and
proceed in the usual manner.
If the blowpipe becomes overheated, it may back-fire. When
this occurs, it may be cooled by plunging it into a bucket of water.
Be sure that the acetylene has been shut off and a small quantity
of oxygen is flowing through the blowpipe to prevent water backing
into the tip and causing further back-firing when the blowpipe is
relighted.
Oxy-Acetylene Blowpipe Flame
Character of Flame. The oxy-acetylene flame consists of two
parts — an inner cone, which is incandescent; and an outer envelope,
or nonluminous flame, which is sometimes called the secondary flame.
The temperature of the oxy-acetylene flame, taken at the extrem-
ity of the inner cone, is very much higher than that of all other flames.
It is calculated to be approximately 6300° F. One of the main reasons
for the superiority of the oxy-acetylene flame over all other welding
lies in the fact that this high temperature is concentrated at the point
of inner cone.
The character of the oxy-acetylene flame depends upon the
proportion of oxygen and acetylene contained in the mixture and
the thoroughness of the mixture as it issues from the tip of the blow-
pipe. Varying proportions of the gases produce three characteristic
types of flame, Fig. 18, called, respectively, reducing, or carbonizing,
flame ; neutral, or welding, flame ; and oxidizing flame. Each type has
its characteristic appearance, and it takes only a little practice to
instantly recognize each. The welder should at all times observe
carefully the type of flame produced and promptly correct any
divergence.
OXY-ACETYLENE WELDING 25
Neutral, or Welding, Flame. A neutral flame is produced when
acetylene and oxygen burn in the proper proportion, theoretically
1.00 volume of oxygen to 1.00 volume of acetylene. The appearance
of this flame is characteristic, Fig. 18 b. It is made up of a distinct
and clearly defined incandescent cone, or jet, of bluish hue, surrounded
by a faint secondary flame, or envelope, purplish yellow in color and
of a bushy appearance.
The incandescent cone may be from T£ to f inch in length and is
usually rounded or tapered at the end. The maximum temperature
of the oxy-acetylene flame is TG to ^ inch beyond the extremity of
this cone.
Fig. 18. Oxy-Acetylene Flame. Top, Reducing Flame; Middle, Neutral Flame;
Bottom, Oxidizing Flame
The middle illustration in Fig. 18 shows roughly the character-
istic appearance and formation of the neutral, or welding, flame.
This flame is the one most extensively used, and no welder is proficient
until he is thoroughly familiar with its appearance and distinguishing
characteristics and is able to maintain this flame under working
conditions.
Flame Regulation. The neutral flame is obtained by starting
with a flame having a slight excess of acetylene and gradually cutting
down the acetylene supply by means of the blowpipe needle valve.
As this is done, the streaky appearance of the inner cone will
26 OXY-ACETYLENE WELDING
gradually diminish. The flame is neutral when the streakiness just
disappears.
Carbonizing, or Reducing, Flame. The reducing, or carbonizing,
flame is produced when there is an excess of acetylene in the flame.
This flame is of an abnormal volume, dirty yellow in color, of uniform
consistency, and has a streaky appearance. By gradually decreasing
the acetylene supply at the needle valve, the size of the flame is
decreased, and gradually a white cone of great luminosity appears at
the blowpipe tip. The extent .of the reducing, or carbonizing, action
of the flame is judged practically by the size and definition of the
luminous cone. When this cone becomes more clearly defined and
takes the form and color of a bluish white incandescent cone, or pencil,
the streakiness is further diminished, and the flame approaches the
neutral stage. The upper illustration in Fig. 18 shows a reducing, or
carbonizing, flame that has a fair but not large excess of acetylene.
The temperature of the reducing flame is considerably lower than that
of the neutral flame.
Use of Reducing Flame. A slight excess of acetylene is used in
the welding of brasses, bronzes, aluminum, and certain alloy steels
to guard against the burning out of easily oxidized elements. It has
also been used in the case of certain mild steels to increase the carbon
content to secure greater hardness. In this connection it must be
remembered that increase in hardness is usually accompanied by
decrease in strength, so that in general welding an excess of acetylene
should not be used.
Oxidizing Flame. An oxidizing flame is produced when there is
an excess of oxygen in the flame. The effect of too much oxygen is to
diminish the size of the flame, blunt or blurr the inner cone, and pro-
duce a weak, streaky, or scattering flame. In some blowpipes, the
inner cone is not only diminished in size but is slightly bulged at its
extremity as compared with the neutral flame, which is shown in
the middle of Fig. 18. The lower illustration in Fig. 18 shows the
oxidizing flame.
Caution Against Oxidizing Flame. An oxidizing flame should be
carefully guarded against or it will become a source of trouble. An
excess of oxygen will burn the metal, causing weak welds, and in the
case of cast iron it will produce a hard weld that will be difficult to
machine.
OXY-ACETYLENE WELDING
27
Manipulation of Blowpipe
Position of Hose. Occasionally
operator's shoulder. In this case the
pended and held by the hose so that it
peculiar welding motion to the
blowpipe, which can usually be
done by the fingers. However, this
method is not generally recom-
mended, as it seriously hinders the
free movement of the welding
flame. It should be used only as
a relief when the work is of long
duration and the operator's wrist
and forearm become tired.
Position of Blowpipe. The
operator, having lighted the blow-
pipe and properly adjusted the
flame, is now ready to begin weld-
ing. Grasp the blowpipe firmly
in the hand, as shown in Fig. 19.
The blowpipe is so designed that it
balances properly when grasped at this
to hold the blowpipe in the fingers,
and Welding Rod
the hose is thrown over the
weight of the blowpipe is sus-
is only necessary to impart the
Fig. 19. Correct Method of Holding
Welding Blowpipe
point. It is not good practice
because it is not possible to
Fig. 20. Blowpipe Should
Not Be Inclined Too Much
^.6. -.. Blowpipe Should
Not Be Held Too Vertical
Fig. 22. Blowpipe Should
Not Travel Backwards
manipulate the flame with as great regularity and control, nor will
it be possible to do as heavy work without tiring.
Inclination of Blowpipe. The head of the blowpipe should be
inclined at an angle of about 60 degrees to the plane of the weld.
28 OXY-ACETYLENE WELDING
The inclination of the head should not be too great, Fig. 20, because
the molten metal will be blown ahead of the welding zone and will
adhere to the comparatively cold sides of the weld. On the other
hand, the welding head should not be inclined too near the vertical,
Fig. 21, or the secondary flame will not be utilized to its full value for
pre-heating the metal ahead of the actual welding.
In ordinary welding practice it is best that the top of the blow-
pipe be so inclined and so directed that the maximum amount of pre-
heating is obtained without blowing the molten metal ahead.
Travel of Blowpipe. • The travel of the blowpipe should be away
from the welder and not toward him, Fig. 22, as the work can be
observed more closely and done more easily and quickly.
Movement of Blowpipe. In making a weld a simultaneous fusion
of the edges of the parts to be joined and the welding rod is necessary.
If this does not occur, a true weld is not produced.
Fig. 23. Circular Motion of Blowpipe for Fig. 24. Oscillating Motion of Blowpipe
Welding Light Sections for Welding Heavy Sections
In the case of parts which have been chamfered out and which
require the use of filling material, a peculiar motion must be imparted
to the blowpipe, which will take in both edges of the weld and the
welding rod at practically the same time.
In comparatively light work a motion is imparted to the blowpipe
which will cause the incandescent cone to describe a series of over-
lapping circles, as shown in Fig. 23. This overlapping extends in the
direction of the welding. This motion must be constant and regular
in its advance so that the finished weld will have a good appearance.
The speed of progress should be such that complete fusion of the three
members referred to is secured. The width of this motion is depend-
ent upon the size of the material being welded and varies accordingly
with the nature of the work. It does not take much experience to
establish the proper size motion and the proper rate of advance for
the various sizes and kinds of metals.
OXY-ACETYLENE WELDING
29
In very heavy work, if the above system were used, a great deal
of the motion would be superfluous. Consequently, a movement
in which the cone of the flame will describe semi-circles should be used,
as shown in Fig. 24. This confines the welding zone and concentrates
the heat. While the progress is not so fast, it is more thorough than
the other system for this class of work.
Importance of Movement. To the average beginner the regular
control from these motions is difficult. It requires considerable
practice and experience to become skilled in this, but it is the regu-
larity of these motions that produces the characteristic rippled surface
of good welding. The progress of a welder and the quality of his
work can be determined to some extent by the skill with which he
produces this effect.
Position of Welding Rod.
After the beginner has mastered the
peculiar motions of the blowpipe,
his next step will be to properly
introduce the welding rod into the
weld in such a manner that the
regular advance of the blowpipe
will not be hindered or retarded.
The welding rod, or wire,
should be held and inclined, as
shown in Fig. 25. In this position a sufficient quantity of material
may be added at the right time. If the welding rod were held in a
vertical or horizontal position, the welder would be liable to add an
excess of metal, part of which would not be properly fused.
When to Add Welding Rod. Great care must be taken in adding
this metal that the edges of the weld are in their proper state of fusion
to receive it. If the metal is not hot enough, the added material will
simply adhere to the sides, resulting in' adhesion only, not a true weld.
It is, therefore, necessary to produce equal fusion at the edges of the
weld with that of the welding rod by the correct motion of the
blowpipe.
How to Add Welding Rod. When the proper time arrives to add
the filling material, the welding rod is lowered into the weld until it is in
contact with the molten metal of the edges. When in this position the
flame of the blowpipe is directed upon it, and thus fusion is produced.
Fig. 25.
Correct Method of Holding
Welding Rod
30 OXY-ACETYLENE WELDING
In welds of unusual depth the end of the rod is immersed in the
molten metal and the blowpipe flame is played around it. The
material is thus protected from the air and the gases of the blowpipe.
The heat of fusion in this case is supplied mostly from the molten
metal which surrounds the rod.
Faults to Be Avoided. The usual faults of the average beginner
are : first, failure to introduce the welding rod into the welding zone
at the proper time; second, to hold
the rod at the wrong angle; and
third, to fuse either too little or
too much of the rod. The filling
material when melted should never
be allowed to fall into the weld in
drops, or globules, Fig. 26.
Building Up the Weld. In
welding it is customary to build up
the welded portion in excess of the
AiFk-J?6; ^e,1,di-nf Rov s^¥ Not Be thickness of the original section.
Allowed to Fall into the Weld in Drops
There are several reasons for doing
this. First, the weld is reinforced and the strength is accordingly
increased. Second, in case it is desired to finish the surface there is
sufficient stock to allow machining. Third, in some cases small pin-
holes or blowholes may be found just under the surface of a weld,
which do not extend to any depth in the weld and may be removed
by filing or machining.
GENERAL NOTES ON WELDING
The above are basic principles involved in producing all good
oxy-acetylene welds. There are many detailed operations which
must be learned by practice for the successful handling of the
different metals, but by keeping in mind these basic principles and
by applying them properly, the more difficult operations can be readily
mastered.
Haste Fatal to Good Welding. It is a fundamental rule for
successful welding that the operator must give his undivided attention
to the work in hand. Do not try to hurry over or slight any step of the
work. You cannot weld faster than the metal will melt and fuse
together.
OXY-ACETYLENE WELDING
31
Fig. 27. Method of Filling in a Deep
Hole— Start at the Upper Edge
Burning a Hole in the Metal. Occasionally an operator becomes
so interested in some minor detail of his work that he allows the flame
to burn through the metal and form
a hole.
How to Weld Up a Hole. It is
a difficult operation for a beginner
to fill these holes. His first at-
tempts usually result in enlarging
the holes instead of closing them.
The proper way to take care of
this is to incline the blowpipe so
that the flame is almost parallel to
the surface of the work, Fig. 27.
With the blowpipe in this position,
play the flame upon the upper edge of the hole until the sides become
plastic, taking care that the edges do not become entirely fused.
When the edge is in the proper condition, the welding rod is interposed
and a small amount of metal is added to the top edge of the hole.
This operation is repeated until the hole is filled in. As the work pro-
gresses, the blowpipe is gradually raised until it resumes its normal
position.
Overhead and Vertical Welding. In welding overhead, Fig. 28,
or vertically, Fig. 29, the same
procedure is followed as in filling a
hole. The metal should not be
allowed to reach the state of fusion
that is secured in ordinary weld-
ing. It should be hot enough to
assimilate the welding rod, but not
so fluid that it will flow out of the
weld. In overhead welding care
should be taken that oxidation
does not occur, because the
molten oxide will flow from the
weld and seriously inconvenience Fig. 28. Overhead Welding
the operator.
Beginning a Long Weld. In beginning a long weld pains should
be taken to see that it is started properly, and at this point of the
32
OXY-ACETYLENE WELDING
work time should not be spared. When the weld is properly started
the speed may be increased. As the weld advances the speed becomes
Fig. 29. Vertical Welding
greater, because the material becomes heated up and the blowpipe
action is faster.
Defects in Welds. There are a number of sources of defects
in welds, and the average beginner usually encounters all of them
before he becomes a skilled welder.
Improper Flame Adjustment. If the flame is not properly
adjusted the weld will be inferior. The commonest fault is the
presence of too much oxygen in the welding flame. Unless the
operator takes a great deal of care in removing the oxidized particles,
they will be incorporated in the weld, Fig. 30. The oxide, of course,
Fig. 30. Oxidized Weld
Fig. 31. Failure to Completely Penetrate to the
Bottom of the Weld
greatly decreases the strength and greatly affects the other mechanical
properties of the weld.
OXY-ACETYLENE WELDING
33
Adhesion of Added Metal to Edges of
the Weld
Failure to Penetrate. A fault, not only of the beginner but also of
the skilled operator, is failure to penetrate to the bottom of the weld,
Fig. 31, and is the cause of a great many defective welds. In his
desire to complete a weld as soon as possible, the operator very often
hastens over the most important
part of the work, which is to
secure the absolute fusion of the
edges at the bottom of the weld.
Failure to do this not only Fig. 32.
reduces the section of the metal
at the weld, but also gives a line of weakness in case the welded
pieces are submitted to bending or transverse strains.
Adhesion of Added Metal. When molten metal from the welding
rod is added to the edges of the weld which are not in fusion, a weld
is not secured. The added metal merely adheres to the cooler metal,
Fig. 32, and perfect fusion is not secured. Adhesion may be caused
by improperly chamfering the pieces to be welded, by improper incli-
nation of the blowpipe, by improper use of the welding rod, or by
faulty regulation and manipulation of the welding flame.
The tendency of beginners is to not prepare the pieces properly
for welding. Usually the chamfering, or grooving, is either not deep
enough, that is, does not extend entirely through the section to be
welded, or it is not wide enough. In welding pieces improperly
prepared the tendency of adhesion is great.
The most common fault is the addition of the welding rod to the
edges of the weld before they are in fusion. The adhesion in this case
is applied to both edges. Sometimes one edge of the weld is in fusion,
but the other is not. In this case adhesion is applied to only one side,
Fig. 33. Weld Not Properly Reinforced Fig. 34. Weld Properly Reinforced
but with the effect that the strength of the weld is lessened the same
as when adhesion occurs on both sides.
In some cases the edges of the metal are brought to a state of
fusion too soon, so that oxide has an opportunity to form on the edges
34 OXY-ACETYLENE WELDING
of the weld. Then, when the welding rod is added, adhesion occurs
with a film of oxide separating the edges and the added material.
Often an operator will concentrate the flame upon the welding
rod and the edges of the weld. Then, as the blowpipe is played
around the welding rod, some of the molten metal is forced ahead.
The metal ahead is not in the proper state of fusion and consequently
adhesion results.
Insufficient Reinforcing. It is not uncommon to see welds
produced that do not contain enough metal, Fig. 33. All welds
should be reinforced with additional metal as in Fig. 34. In case a
smooth finish is desired this excess metal can be removed by grinding
or machining. Too great an excess of metal must not be added be-
cause this takes extra time and the gases are wasted.
WELDING FOR DIFFERENT METALS
PROPERTIES OF METALS
Before the beginner takes up the actual welding of metals, it is
necessary that he study their properties, peculiarities, and behavior
under the action of the welding flame. Some of the physical proper-
ties of the more common metals are given in Table I.
. Melting Point. The first property that the welder should
consider is the melting point or temperature at which the metal will
fuse or become fluid. The average welder is usually fairly familiar
with the difference in melting points of lead or zinc, and iron or steel ;
but he is usually not familiar with the difference between the melting
points of brass, bronze, copper, white cast iron, gray cast iron, etc.
This knowledge is especially important if it becomes necessary to weld
members of dissimilar materials.
Thermal Conductivity. The conductivity of a metal is its
ability to transmit heat throughout its mass. This property, which
is not the same for all metals and varies within wide limits, is of great
importance to the welder. It can be seen that if one metal conducts
or transmits the heat from the welding blowpipe more rapidly through-
out its mass than another, it is necessary that allowance be made both
as to the pre-heating equipment and the size of the blowpipe used.
In welding metals of high thermal conductivity, it is necessary
to use oversize blowpipes — as in the case of copper. Although the
OXY-ACETYLENE WELDING
35
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36 OXY-ACETYLENE WELDING
melting point of copper is low, yet the conductivity is high, and,
consequently, a blowpipe of the same size as would be used on a
similar section of steel must be used.
The conductivity of a metal will have a great bearing on the
consideration of expansion and contraction. If one metal absorbs
or leads the heat away from the welding blowpipe more rapidly than
another, the heated area will become very much larger, and, conse-
quently, the expansion and contraction more severe.
Specific Heat. The specific heat of a metal is the amount of
heat that is absorbed when it is raised through a certain range of
temperature. A metal having a low melting point but relatively
high specific heat may require as much heat to bring it to its point of
fusion as a metal of high melting point and low specific heat — as in
the case of aluminum compared to steel.
Coefficient of Expansion. The linear increase per unit length
when the temperature of a body is raised through one degree is its
coefficient of expansion.
The coefficient of expansion varies materially with the different
metals. Of the metals most commonly welded, as seen from Table I,
aluminum has the greatest expansion, bronze and brass next, then
copper, steel, and iron. Aluminum expands almost twice as much
as iron or steel, consequently, in dealing with aluminum work it is
necessary that this feature be considered very seriously.
Expansion and Contraction. When a body of any material is
subjected to an increase in temperature, it expands and its volume
and linear dimensions are increased. When the temperature is
lowered a reverse action takes place, the body contracts, and its
volume and linear dimensions decrease. Metals or metallic bodies
are very susceptible to this change in volume due to variations in
temperature.
The effect of this expansion and contraction is of great impor-
tance to the welder. It is impossible for the welder to produce satis-
factory work until he has a knowledge of the nature and the amount
of expansion usually encountered and of how to compensate for it.
The expansion and contraction of the welded piece cannot
be controlled or arrested mechanically, because the force of expansion
is irresistible. In malleable, or ductile, metals the expansion is liable
to produce warping or deformation of the piece, while in materials
OXY-ACETYLENE WELDING
37
that are not of this nature — brittle materials — such as cast-iron, the
result of the expansion and contraction, unless properly taken care of,
is fracture.
If the expansion can take place in all directions, it will give the
welder no trouble, as the piece will expand equally all over, and upon
cooling will contract to its original volume. If, however, the welding
takes place at a point that is confined by various parts or by the par-
ticular construction of the piece, it is then necessary to give it due
consideration.
The resultant effect of contraction, produced by the cooling of
the welded object, must be considered equally with that of expansion.
Contraction produces as much cracking, or checking, and warping as
does expansion. Therefore, it is essential that the welder study not
only the effect of expansion, but also the subsequent result produced
.by contraction.
Methods of Handling Expan-
sion and Contraction. There are
many ways of taking care of
expansion and contraction, such
as heating the entire piece to a
dull red heat, simultaneously
heating opposing similar parts,
and breaking the piece at certain
points to allow free expansion and then re-welding at the break. If the
material is ductile or malleable, it may be warped or bent out of
shape to such an extent that the spring will take up completely the
opposing force of expansion and contraction. This, however, entails
an accurate calculation and should not be used except where no other
means are feasible.
Handling Simple Case of Expansion and Contraction. We will
first consider the simplest condition of welding. Assume that a long
bar which is free at each end has broken at point A, Fig. 35. In this
case the welding may be carried out without any fear of encountering
difficulties due to expansion and contraction. The bar is free to
expand and contract at each end. While there might be some warp-
ing or deformation due to the heat of welding if the blowpipe is not
handled properly, yet, there is very little danger of weakening the
weld because of internal strains.
Fig. 35. Simple Case of Expansion and
Contraction
38 OXY-ACETYLENE WELDING
Now let us assume that this bar is part of a casting, as shown at C,
which is surrounded and joined to a rigid frame B and D. In this
case the expansion and contraction due to welding must be taken
care of. It is readily seen that the expansion is not the force that will
cause trouble, because when the two pieces expand during welding,
the metal, which is in a fused condition, is so soft that the expansion
can take place in the weld and the edges will approach each other.
This will not affect.the confined frame. However, consider the action
on the metal when it starts to cool. Contraction sets in and, as it is
irresistible, there must be some compensation for the shortening of
the bar C. If the material is ductile and one that will stand bending,
deformation or warping will occur. But, if it is of low ductility, such
as cast iron, a break will occur either at the weld or at a line of less
resistance.
Methods of Handling. In welding an article of the general
nature, shown in Fig. 35, when the break is in an internal member,
such as at C, there are several ways of handling it.
Heating Entire Casting. The entire piece can be raised to a high
temperature as referred to above and in this way produce an expan-
sion in the entire mass, and, consequently, equal contraction. How-
ever, this is not necessary, and in some cases is not possible; the
operation also takes more time and costs more. It is only necessary
at the time of welding to heat simultaneously similar parts to a good
red heat, in order that the stiffness of the frame may be lessened, and
thus take care of the contraction.
Heating Confining Members. In the example referred to, the
application of a pre-heating burner at the points B and D will cause
the frame to expand in the linear direction of the expansion and con-
traction produced by the weld. Therefore, when the weld is finished
and the frame starts to cool and contract, the parts B and C, in as
much as they were raised to practically the same temperature as the
metal surrounding the weld, will contract equally and, therefore, a
successful weld will be produced.
Use of Wedges. If it is impossible to apply pre-heating at the
points referred to, another method may be used. By the use of
jacks, wedges, or similar devices, a casting such as shown in Fig. 35
may be sprung or bent out of shape, and the edges of the part to
be welded may be separated. After the weld is executed and con-
OXY-ACETYLENE WELDING
39
traction sets in, the jacks, wedges, etc., may be withdrawn. The return
of the sprung parts to their original positions will compensate the
contracting strains.
Breaking Another Member. Another method of taking care of
expansion and contraction is that of breaking the piece at some extra-
neous point, such as at E. In this case the expansion and contraction
will be free to act at the point C without any fear of serious after-
effect, as the casting is free to spring in any direction, because of the
loose joint at E. As the point E is not confined, it is an easy matter
Fig. 36. Complex Case of Expansion and Contraction
to reweld this break without fear of any bad results. This method,
however, is dependent upon the thickness of the metal and is one
that should not be attempted unless no other means are feasible.
While this diagram is extremely simple, nevertheless the prin-
ciples to be considered and the methods of handling them are indenti-
cal with those experienced in all practical work. A clear conception
of the forces acting, the nature of their action, and how to counteract
them, is essential in work with the oxy-acetylene blowpipe.
Handling Complex Case of Expansion and Contraction. A good
example of a complex case of expansion and contraction is the fly-
wheel or pulley with broken spokes, as shown in Fig. 36.
40 OXY-ACETYLENE WELDING
Assume that the spoke is broken at A. If this were welded with-
out considering and allowing for expansion and contraction, the
shrinkage strain would be so great that failure would occur.
Pre-heating the rim from W to X to a dull red heat will cause the
rim to expand outwardly, separating the edges of the broken spoke.
While in this state the weld should be made rapidly and then the
entire wheel allowed to cool slowly. Thus a good weld without the
presence of internal strains will be produced. The expansion of the
rim, due to the pre-heating, will offset the contraction of the weld
in the spoke.
If the crack in the spoke is near the rim, it is only necessary to
apply a gas or oil burner to the rim at M until it is at a red heat.
This will expand the spoke and rim, and separate the edges of the
break sufficiently to offset the contraction of the weld.
The spoke may be welded at A without pre-heating if the confin-
ing member — in this case the rim — is broken to lessen the rigidity.
In order to do this the rim must be broken at a point P, always close
to the spoke. First one side of the spoke is strongly tacked at the
weld. Then the other side is welded two-thirds the way through.
The tack is then melted out and the weld completed. The rim is then
welded at point P. If the edges do not meet accurately, they may be
brought to do so by heating either at M or 0, according to which edge
is low.
If two spokes are broken as at A and B, the same general pro-
cedure as given above may be followed. In case it is necessary to
pre-heat a large portion of the casting it is important that the pre-
heated area always extend beyond the spokes adjacent to those
fractured, from Y to Z.
If two diametrically opposite spokes are broken such as B and C,
each may be treated as independent of the other and welded by any
of the methods given above.
PRE-HEATING
Reasons for Pre=H eating. Pre-heating is employed for three
fundamental reasons:
To Compensate for Expansion and Contraction. When pre-heat-
ing is used to counteract the effects of expansion and contraction, it
is necessary that the casting be heated either in certain confined
OXY-ACETYLENE WELDING 41
localities or entirely to a dull red, or in some cases to a bright red heat.
With this treatment the internal strains existing in all welds are
reduced to a minimum.
To Decrease Cost of Welding. When a weld is being executed
on a large casting, it is too expensive to supply the total amount
of heat required from the blowpipe alone. To offset this, pre-heating
by some cheaper method is used, and the result is usually a saving
of from 25 to 60 per cent of the cost of welding by means of the blow-
pipe alone. Then, too, it is possible to accomplish the welding with
greater speed, due to the casting being at a higher temperature.
To Make Metal More Receptive to Action of Welding Flame. When
the temperature of a metallic body is raised, the state of the metal
Fig. 37. Pre-Heating with Welding Blowpipe Fig. 38. Gas Burner for Pre-Heating
surrounding the weld is more nearly that of the molten metal in the
weld, and the result is a more homogeneous and smoother-grained
union, dependent upon the temperature reached in pre-heating.
Methods of Pre=Heating. There are various means of carrying
out this preliminary heating. The method used should be governed
by the particular work in hand.
Pre- Heating with Welding Blowpipe. The simplest method and
the one most used on light objects is that of utilizing the flame of the
welding blowpipe, Fig. 37. In welding thin castings, it is only
necessary that the flame of the blowpipe be played upon the parts at
the line of the weld for a few moments, in order that the pieces may
obtain a red heat. This is, however, expensive, and should only be
employed on small objects.
42
OXY-ACETYLENE WELDING
Gas and Oil Burners. If the article to be welded is of fairly large
size, the use of gas, Fig. 38, or oil burners, Fig. 39, is economical.
Fig. 39. Oil Burner for Pre-Heating
Courtesy of Oxweld Acetylene Company, Chicago, Illinois
Fig. 40. Charcoal Fire for Pre-Heating Castings
These pre-heating torches, however, limit the area of the surface
covered, so consequently are used more successfully on that work
OXY-ACETYLENE WELDING 43
which requires localized pre-heating. The flames produced are of
sufficient temperature, but not the necessary volume to evenly heat
the entire casting.
Charcoal Fire. The most satisfactory method of pre-heating is
by means of a charcoal fire built around the article to be welded.
The usual procedure is to build a small temporary fire-brick furnace
around the piece and fill in with charcoal, Fig. 40. This is ignited by
means of kerosene. As the progress of the ignition of the charcoal
is rather slow, the pre-heating is carried out gradually. The nature of
this pre-heating flame is of such evenness and volume that the tem-
perature imparted to the casting is the same throughout its mass.
In welding large castings of a complicated nature, such as engine
cylinders, it is necessary that they be pre-heated evenly throughout
and that the welding be carried on while the casting is at a dull red
heat. Therefore, the most satisfactory means of accomplishing this
is by embedding the casting in charcoal and carrying on the work
while it is embedded in the hot coals.
STEEL WELDING
General Considerations. The welding of steel is apparently
simple, but in reality it is a fairly difficult material to weld and
should receive the welder's best thought and care. It is simple to
produce a nice looking weld that has a smooth even surface, but it is
not easy to produce a weld that is strong and will stand up under
service. Welds of high strength are absolutely necessary in cases like
automobile frame and crankshaft repairs, because a poor weak weld
might prove fatal.
Oxidation. It is practically impossible to prevent a certain
amount of oxidation; but it is very important that it be kept to a mini-
mum. The oxide that forms on the top of the weld may be removed
quite easily, because it melts at a lower temperature than the metal.
It may be floated off the weld while hot, or removed as a thin skin
after the weld becomes cold. Care must be taken, when adding the
welding rod, Fig. 30, page 32, that this film of oxide is penetrated,
because if this is not done the oxide will be incorporated in the weld,
which will therefore be very weak.
Expansion and Contraction. The effect of expansion and con-
traction is not as severe in steel welding as in cast iron or aluminum;
44 OXY-ACETYLENE WELDING
but, nevertheless, it must receive due consideration. In steel castings
it is taken care of in a manner similar to that used for cast iron, that
is, by pre-heating. In sheet-steel work the creeping, or drawing, of
the edges is taken care of by arranging the edges of the sheets at an
angle, or by tacking, or by the use of jigs to hold the work.
Welding Rod. Each welding head is designed for use with a
certain thickness of metal. As the volume of the flame varies with
the size of the welding head, care must be used to select a welding
rod of the correct size in making welds in sheets of various thickness.
There is great danger of burning a welding rod that is too small, or,
if the rod is too large, it may not melt through and will enter into the
weld in a semifused condition and not be thoroughly incorporated in
the weld. The following table shows the proper size of welding rod
to be used for the different thicknesses of sheets:
THICKNESS OF SHEET SIZE OF WELDING ROD
Up to J inch TQ inch
I to A inch J inch
J to f inch A inch
| inch and over J inch
Never use twisted wire made up of two or more strands, because
this offers a very large surface for oxidation, which is a condition
operators must try to avoid.
Neutral Flame. The importance of maintaining a neutral flame
at all times cannot be emphasized too strongly. An excess of acety-
lene in the flame tends to carbonize the work, resulting in a hard
brittle weld; while an excess of oxygen will oxidize or burn the metal.
It is seldom necessary to adjust the flow of gases through the blowpipe
after correct adjustment has once been made, except in the case of
very heavy welding where the intense heat of the molten metal tends
to expand the orifice in the tip of the welding head. This has some
effect on the size and shape of the flame and necessitates more or less
frequent adjustment to keep the gases in correct proportion to main-
tain the neutral flame.
Movement of Blowpipe and Addition of Welding Rod. In welding
sheet steel, it is necessary that the oscillating movement previously
referred to be imparted to the blowpipe and used continuously—
both because of its high-melting point and the behavior of the molten
metal under the action of the blowpipe flame. Steel cannot be pud-
OXY-ACETYLENE WELDING 45
died and it is therefore necessary to add the filling material in thin
overlapping layers. The importance of securing a perfect bond
between every two layers can be readily seen. To make a true weld,
a simultaneous fusion of the edges of the sheets and the welding rod
must be produced.
To do this with light- and medium-weight sheets, a motion is
imparted to the blowpipe which will cause the flame to describe a
series of overlapping circles as previously described, page 28. This
overlapping extends in the direction of the welding and, in order to
make a weld of good appearance, must be constant and regular in
its advance.
In heavier plates, while the same rule governing simultaneous
fusing of the edges of the sheets and welding rod apply, the filling of
the groove is accomplished in a slightly different manner. On
account of the depth of the weld the flame is not large enough to
fuse a body of metal of so great an area, and it is impossible to fill the
groove entirely from bottom to top with one layer of metal. The
bottom edges of the groove must first be thoroughly fused for an inch
or two before adding metal. When this is done, bring the flame back
to the starting point and when the metal is in the proper molten
condition add the filling material, oscillating the blowpipe in a series
of semicircles, as previously recommended for welding heavy sections,
page 29. Follow this method of filling the groove in sectional layers
until the proper height is reached, making sure that thorough fusion
is accomplished between the layers themselves and the edges of the
sheet and the layers of filling material.
After- Treatment. Correct after-treatment is as essential for
successful welding of steel as the actual welding operation. Proper
after-treatment will improve the grain of the metal and will materially
increase the strength and toughness of the weld. There are three
principal treatments that will benefit the material and are easily
employed in the repair shop. These are called annealing, hammering,
and quenching.
Annealing. Annealing consists of reheating the work to the
proper temperature and then allowing it to cool slowly. The work
should be heated to a bright cherry red by means of a blowpipe or
suitable burner, or in a furnace that can be carefully regulated. Care
must be taken that the work reaches the bright cherry red, because
46
OXY-ACETYLENE WELDING
heating to a lower temperature will be detrimental and may leave the
weld weaker than if not annealed at all. After the work has been
heated, it should be allowed to cool very slowly and evenly. It
should be covered over with asbestos or dry sand, packed in lime, or
left to cool in the furnace. Care must be taken that cold air currents
do not strike the work before it has become cold.
Hammering. Hammering consists of reheating the weld to
the proper temperature and then hammering while at this tempera-
ture with a hand hammer. The weld should be heated to a bright
yellow heat and then hammered with quick light blows. Heavy
hammers or heavy blows should never be used. The hammering
should cease as soon as the weld falls to a dull red, for otherwise
the fine grain of the metal will be spoiled and the weld will be weak.
Quenching. Quenching consists of reheating the work to the
proper temperature and then plunging it into water, brine, or oil.
This method is used mainly for small articles. It is used quite often
for hardening and tempering. Quenching should be employed only in
special cases, because, although it will make the work strong, it will
also make it hard and brittle.
Light Sheet-Steel Welding
Preparation. In welding two short pieces of flat steel, up to A
inch in thickness, no special preparation of the plates is necessary,
except to have them flat as possible
and to be sure that the edges are
reasonably true. The two pieces of
metal should be placed on a level
surface, preferably fire brick or
some other nonconductor of heat.
Expansion and Contraction.
With light sheet, expansion and
contraction are cared for by tacking
the seam at certain intervals or by
arranging the sheets so that the
edges to be welded are set at a
slight angle rather than parallel,
Fig. 41. Light Sheets in Position for
Welding
Fig. 41. The correct amount of divergence is determined by the
thickness of the metal and should be from 2J to 6 per cent of the
OXY-ACETYLENE WELDING
47
length of the weld. The amount of divergence between these limits
varies also with the speed of welding, fast welding requiring less
spread. After the plates are in this position, place two pieces of flat
bar steel on each side, about \ inch from, and parallel to, the line of
the weld. Clamp or weight these pieces down so that they cannot
be readily moved. The work is now in position for welding.
Jigs. In making this type of weld in flat sheet steel in longer
lengths, up to several feet and up to ^ inch in thickness, a welding
jig made up with two slotted jaws hinged at one end and provided
with hold-down clamps at the other end will be found more conven-
ient than the individual hold-down bars.
Fig. 42. Jig for Holding Light Sheet Cylinders for Welding
For welding short cylinders, a jig made similar to that shown in
Fig. 42 will be found satisfactory.
Tacking. Tacks, or short welds, at intervals of from 2 to 6
inches, according to the thickness of the sheet, can be made the entire
length of the seam to hold the edges in position for welding if jigs
are not available.
One of the above methods must be used to take care of the
creeping action due to expansion when the flame of the blowpipe
is applied to the metal. If this action is not provided against and
the two sheets are placed with parallel edges, they will first diverge
48
OXY-ACETYLENE WELDING
when the welding is started, as in a, Fig. 43, and then gradually come
together. When about half of the weld has been made, they will again
become parallel as in b. From this point on as the welding continues
the sheets will draw together until they overlap, as shown in c.
(a)
Fig. 43. Result of Not Providing for Expansion
Welding Light Sheet. Select the welding head and a piece of iron
welding rod of the size suitable for the thickness of the sheet and
place the work in position for welding.
As steel is very sensitive to the action of the carbonizing
flame and particularly to that of the oxidizing flame, a constant,
nonvarying, neutral flame should be maintained. The incandescent
jet should be of maximum size and clear outline at all times.
With the correct neutral flame, start welding at the point
where the two sheets meet. Impart the circular motion to the
blowpipe, described under Movement of Blowpipe, page 28, to
produce the correct rippled surface on the finished weld. When the
Fig. 44.
Appearance of Good Weld in Light
Sheet Steel
Fig. 45.
Appearance of Poor Weld in Light
Sheet Steel
weld is finished, turn out the blowpipe and allow the work to cool
until the metal is black.
Then remove the hold-down bars and examine the weld. It
you have followed instructions, your weld will have the appearance
shown in Fig. 44 and will not be like that shown in Fig. 45. On
OXY-ACETYLENE WELDING
49
Fig. 46. Lai
Should Never :
Welds
tellsed
Fig. 47. Butt Weld in
Light Sheet
closer examination you will find that all the particles of dirt and
impurities you noticed floating on the top of the molten metal when
you were welding are now lying with the oxide
on top and alongside of the weld where they can
be readily brushed or scraped off. Now take
your job to the shears and cut off one or two
pieces. Upon examination, the cross-section should present the
same uniform texture and color in both the weld and the sheet.
Types of Welds in Light Sheet. Lap Weld. Lap joints, either
single or double, Fig. 46, should never be used
in welding sheets of any thickness because
the weld will be subjected to a shearing strain.
Welds should be under tension or compres-
sion strains, never under shearing or bending strains.
Butt Weld. The most common and the simplest weld to prepare
in light sheet is the butt joint, shown in Fig. 47.
Flange Weld. Another type of weld in light*
sheet, but one that entails some preparation, is Fig-
made by flanging up the welding edges about ^
to YQ inch, Fig. 48, laying the two pieces flat and parallel on the weld-
ing table and executing a flange, or
edge, weld. It is not necessary to
use welding wire with this type of
weld, because the metal in the
flanges when they are fused to-
gether acts as a filling agent. By
careful manipulation the edges can
be fused down to a small bead,
practically flush with the surface
of the sheet.
Cylinders. In welding light
sheets that have been rolled in
cylindrical form, the separation of
the edges can be accomplished by
placing a wedge about two-thirds
Fig. 49. Method of Welding Light Sheet
Cylinders — Using Wedge to Space the Edges
of the way down the length of the seam after the welding is started,
Fig. 49. As the welding progresses the wedge should be moved further
along the seam and withdrawn entirely as the work nears completion.
50
OXY-ACETYLENE WELDING
Tacking can also be resorted to in welding cylindrical forms,
although this results in the deformation of the cylinder, as shown
in Fig. 50, and makes it necessary
to hammer or re-roll the cylinder
into shape.
The edges of very light sheet
cylinders can be flanged and an
edge, or flange weld, executed; but
this method cannot be recom-
mended with sheets heavier than
TS inch.
Corner Welds. In making a
corner weld in the lighter gage
sheets up to A inch, the edges of
the sheet should be flanged, as
shown in Fig. 51. In sheets from
i^ to A inches in thickness, it is
only necessary that the edges of
Fig. 50. Result of Tacking a Light Sheet
Cylinder — The^Weld Draws up Pointed
the sheets run as true as possible in position, as shown in Fig. 52.
Tacking is necessary in this case, as the sheets, due to expansion,
r~
Fig. 51. Corner Weld
for Very Light Sheets,
up to A Inch Thick
Fig. 52. Corner Weld
for Light Sheets, & to
A Inch Thick
g. 53. Sharp Corner
feld for Light Sheets
readily move out of position when welding is commenced. On welds
of this latter type it is necessary to use welding wire.
Two other forms of corner
welds are illustrated in Figs. 53
and 54. These sheets should be
tacked and, if YS incn or thicker,
welding wire should be used.
Tank Heads. In making
tanks when either a bottom or heads in both ends are required, the
method of putting in the heads is governed by the design and pur-
pose for which the tank is intended.
Fig. 54. Broad Corner Weld for
Light Sheets
OXY-ACETYLENE WELDING
51
Storage Tanks. If the tank is to be used as a storage receptacle,
such as gasoline tanks, the heads can be cut to the outside diameter
of the shell, laid flat on the end of the shell and tacked at intervals
all the way around, Fig. 55. Then the shell, with the heads securely
tacked in place, is laid on its side and the welding is started at any
point, the tank being turned, from time to time, as the welding
progresses. Or, the heads can be flanged to any depth desired,
and backed into the shell until the edge of the flange and the edge of
the shell are even, Fig. 56, making sure that the head fits the shell
snugly. They are then tacked and welded in an upright position.
This latter method is the better of the two from the welding stand-
point.
Pressure Tanks. When a tank is built to stand a considerable
pressure, such as air-compressor tanks, the heads should always be
dished and flanged, the boiler-maker's standard specifications govern
Fig. 55. Head Weld
for Storage Tanks
Fig. 56. Head Weld for
Storage and Medium-
Pressure Tanks
Fig. 57. Head Weld
for Pressure Tanks
this. The heads can be either backed in and an edge weld made,
Fig. 56, or set up so that the edges of the flange exactly meet the
edges of the shell, Fig. 57. In either case the parts should be tacked
together before welding. In the second case, care should be used
in flanging to have the outside diameter of the flange exactly the
same as the outside diameter of the shell. This method is the best
because the weld is under direct tension or straight pull.
Tubes. Light-weight tubing should be squared off and fitted
nicely before welding is attempted. It should be tacked in several
places and then welded.
Heavy Sheet-Steel Welding
Preparation. In welding heavy sheet metal above TS inch in
thickness, a certain amount of preparation is necessary. The
success of the weld depends in a great measure upon the proper
52
OXY-ACETYLENE WELDING
preparation of the work to be welded. While the preparation is
governed largely by the particular location of the weld and form
of the sheets to be welded, there are certain general rules that must
always be observed.
In making a perfect
weld it is necessary that
the metal at the weld
be completely fused
throughout its entire
thickness. In light sheets
the projection of the
flame is great enough to
produce this result, but heavy sheets would require a flame of such
magnitude that it could not be readily handled. Therefore, in order
to facilitate complete fusion, the edges of the sheets to be welded are
Fig. 58. Heavy Sheets in Position for Welding
Fig. 59. Welding Heavy Plate Steel Cylinder
Note grooving of edges, spacing clamps and wedge about half way along the seam
chamfered or beveled to form a V-groove, the width of this V being
equivalent, or nearly so, to the thickness of the metal.
OXY-ACETYLENE WELDING 53
Expansion and Contraction. With heavy sheet, expansion and
contraction are cared for by observing the same rules of spacing,
Fig. 58, and clamping, Fig. 59, or, in some cases, tacking, in order
to hold the work in position for welding, as described for light
sheets on page 47.
Welding Heavy Sheet. Select a welding head and a piece of
iron welding rod of the proper size to accomplish the work in hand.
Because steel is sensitive to the carbonizing and oxidizing flames,
it is necessary to maintain the correct oxygen pressure and a neutral
flame at all times. In ordinary heavy sheet welding there are two
general methods of procedure, either of which will produce a good
weld when properly executed. These methods may be called weld-
ing by sections, and continuous welding.
Welding by Sections. Welding is started by first playing the
flame of the blowpipe along the edges of the pieces to be welded.
This is done merely as a preliminary heat treatment. The flame
is then played on the bottom of the groove at the beginning of the
weld until the edges are in a molten condition, at which time the
blowpipe is momentarily withdrawn and the molten metal allowed
to flow together. This is done without the aid of any filling material.
Care must be exercised at this point, because successful welding
depends upon complete penetration and perfect union of the bottom
edges. When a perfect union of the two members is secured for
about one or two inches, the welding rod is brought into use. By
playing the flame around the welding rod in contact with the edges
of the weld instead of directly on the welding rod, it is possible
to bring them both to the point of fusion simultaneously. The rod
is then gradually added to the weld, layer by layer, until this par-
ticular section of the weld is built up to the required height. The
flame is then played on the face of the metal just added and on the
bottom of the groove until fusion of these parts is secured. The
welder then repeats the operation described above until the next
small section of the groove is filled up to the proper level. The
welding progresses by means of these small sections, each being built
up completely before another is started.
While the metal is in a fused condition, the velocity of the flame
will cause the molten metal to become slightly indented. The
flame should be withdrawn momentarily, from time to time, thus
54 OXY-ACETYLENE WELDING
allowing the fluid metal to flow back to its normal level, in which
position it will solidify. Skill in steel welding depends greatly on
this manipulation, as the flowing together of the different molten
centers produces the weld.
Continuous Welding. In this method the weld advances con-
tinuously with each addition of metal. By this method the metal
is added in short layers, sloping rather than horizontal. The weld
is started by fusing together the bottom edges of the groove as pre-
viously described. The filling material is then added so that it
will be from f to J inch high at the starting point and slope to nothing
in a length of 1 or 1J inches along the bottom of the groove. This
will give an inclined surface to which the filling material is added
in parallel layers. The added metal being on a sloping plane, the
fusion of the bottom edges is always carried ahead with the welding,
as each layer includes a small section of the bottom of the groove.
Types of Welds in Heavy Sheet. Lap Weld. As explained on
page 49, the lap weld should never be used.
Butt Weld. The beveled or grooved butt joint is the only
welded joint that should be employed on heavy sheets, Fig. 60.
The most satisfactory method of
edges, because tacking is very
Fig. 60. Butt Weld in Heavy Sheets ,., , ,111 i i
likely to not hold on heavy sheets.
Never weld sheets from both sides, because unequal strains
are likely to be introduced by localized heating when working on
the second side.
Cylinders. Heavy cylinders should also be prepared for the
grooved butt weld, for the same reasons as for heavy sheets.
Fig. 61. Corner Welds for Heavy Sheets
Corner Welds. The two most satisfactory corner welds for
heavy sheet are shown in Fig. 61. Although the second is a little
OXY-ACETYLENE WELDING
55
more costly to prepare, it is more satisfactory than the first because
it insures better penetration.
Tank Heads. In welding bottoms or heads in tanks of heavy
sheet, the purpose for which the tank is to be used governs the method
of constructing the heads as it does in welding tanks of lighter gage.
The same general rules apply in both cases, the main difference being
C
Fig. 62. Head Weld for
Storage Tanks
Fig. 63. Head Weld for
Medium-Pressure Tanks
Fig. 64. Head Weld for
High-Pressure Tanks
that the edges of the heavy shells and heads are chamfered, de-
pendent on the design of the tank. All require tacking to hold the
members in position for welding.
Storage Tanks. In the case of putting on a flat head, the edge
of the head only is chamfered, Fig. 62, while in putting in a flanged
head where an edge weld is to be executed, as in Fig. 63, both shell
and head are chamfered to make the V-groove.
P LJ
Fig. 65. Welds for Tank Reinforcing Rings
High-Pressure Tanks. When a head is put in, as shown in
Fig. 64, both the edge of the flange and the edge of the shell are
chamfered. This type of head is the best for high-pressure tanks
because the weld is in tension.
This method also applies to the welding of two cylindrical
shells end to end in making tanks of such dimensions that one
single sheet of steel is not large enough to make a complete shell.
56
OXY-ACETYLENE WELDING
Tank Rings. In welding angle-iron rings to tanks of the same
thickness, it is necessary that the edges of both ring and shell be
Fig. 66. Various Pipe Joint Welds
beveled as at the left, Fig. 65. Two methods of welding heavy
rings to lighter shells are shown at the middle and right. The inside
weld at the right should be only enough to smooth off the joint.
n«BAMBB If too much heat is applied from the
inside there is likely to be trouble from
warping or buckling. Rings should always
u ,__ m~- — ^vJ be tacked to prevent bowing, twisting of
Fig. 67. Welds for Pipe Heads tne rings> an(J buckling of the shell.
Tubes and Pipes. Various tube and pipe welds are given in
Fig. 66.
The methods for closing the end of a pipe with a head are
shown in Fig. 67. The first is the easier and stronger of the two.
ILD. £L
Fig. 68. Welds for Pipe Flanges
Three methods of welding flanges to pipe are shown in Fig. 68.
Hie first method is easier to weld than the second; but the latter
OXY-ACETYLENE WELDING
57
Fig. 69. Preparation of Heavy Forgings for
Welding
is the stronger. The third method is the best method of welding
flanges to pipe, but is, of course, a special type of flange.
Welding Heavy Steel Forgings and Steel Castings
Preparation. In welding heavy steel sections, such as crank-
shafts, axles, and the like, the weld is prepared by grooving or beveling
from both sides. This is done
because it is easier for the oper-
ator to do the work and for the
sake of economy, because by
beveling from both sides less
filling material is necessary and,
consequently, less time and gas
are needed.
Square Sections. Square or rectangular sections of forgings
are best prepared by beveling half way through from each side,
Fig. 69. After the welding has
been carried on from one side,
the piece turned over and the
welding completed from
the second side, there will
probably be a slight bow, or
curve. In the case of forgings, Fig. 70.
this is not objectionable, be-
cause the work can be, and, in fact, should be, reheated and straight-
ened. The reheating in the case of forgings is beneficial to the grain
of the material and the
strength of the weld. With
castings, however, this bend-
ing is not possible. There-
fore, to keep the work in
alignment, it is best to pre-
pare the work as shown in Fig. 70. The welding is carried on two-
thirds of the way through from the first side, and then finished
by turning over and working from the second side.
Round Sections. Round or elliptical sections should be prepared
by beveling the ends to a wedge as indicated in Fig. 71. They should
never be turned down to a point. By preparing the pieces as shown
Preparation of Heavy Castings for
Welding
Fig. 71. Preparation of Round Sections for Welding
58
OXY-ACETYLENE WELDING
in the illustration, the welder will have a flat surface to build his
weld upon. If the work were prepared to a point, the filling material
when added would have no surface to lie upon and would run down
in drops, necessitating burning or melting away when the work
is turned over, and probably resulting in a weak weld with con-
siderable oxide.
Expansion and Contraction. Expansion and contraction will
probably cause very little trouble to the operator in the case of
shafts and other heavy pieces that are not connected. The only
difficulty the operator will encounter in these cases will be the possible
bending, which was noted above, when welding from two sides.
However, if the broken part is confined by rigid members, the work
should be handled either by pre-heating, or one of. the other methods
recommended and ex-
plained under Expan-
sion and Contraction,
pages 36 to 40.
V-Blocks. When
welding shafts, it is ad-
visable to line them up in
position on V-blocks, so
that they may be turned
over and still kept in
Fig. 72. "V Blocks for Welding shaft. alignment, Fig. 72.
Welding Heavy Section. In the case of a heavy section select
the proper size welding head and a piece of welding rod of the cor-
rect analysis for the particular work at hand, and place the work in
alignment. ,
If the section is over or about one inch, it should be pre-heated
by means of a gas or oil burner until it is at a red heat. This will
save oxygen and acetylene, and will bring the material to a tempera-
ture at which it will be more receptive to the action of the welding
flame and thereby insure a more homogeneous weld. If not objec-
tionable to the operator, it is advisable to let the pre-heating burner
play on the work while the welding operation is going on, taking
care, of course, that the materials of combustion of the pre-heating
burner do not strike the molten metal and have a detrimental effect
on the weld.
OXY-ACETYLENE WELDING 59
The welding flame is first played on the edges at the bottom of
the groove until they are in a molten condition. The flame is then
momentarily withdrawn to allow them to flow together and "set",
and form the bottom of the weld. When a perfect union of the bottom
is secured all the way across, the welding rod is brought into use.
By playing the flame around the welding rod and the edges of the
weld instead of directly on the welding rod, it is possible to bring
them to a fusing temperature at the same time. The rod is then
gradually added to the weld, layer by layer, until the entire groove
has been filled up. The welding rod is kept plunged into the molten
metal all the time to prevent oxidation. Any oxide that forms during
the welding is floated to the top and removed by scraping with the
welding rod, or by blowing away with the force of the welding flame.
The welder must be careful that he does not allow the molten metal
to run over the sides of the weld. Each layer is added in such a
way that it extends slightly beyond the end of the groove. Then,
from time to time, as the groove is filled up, the operator smooths
down the two ends.
Hammering. As each section, about \ inch thick, is added
to the groove, the operator stops the welding operation, heats the
work to a bright yellow, and hammers the weld lightly but rapidly
to give it as fine a grain as possible. After the weld has been com-
pleted, it is either hammered or annealed, as directed on page 45.
CAST-IRON WELDING
General Considerations. Many defects are experienced by the
beginner in welding cast iron because of its peculiar properties. The
two principal faults noticed are the production of hard, glassy, and
brittle metal in the weld, and subsequent cracks, breaks, and checks
either in the weld or in the adjacent metal, owing to excessive internal
strains set up by unequal contraction. Both are serious defects, and
the liability of their occurrence is so great that proper preventive
methods should be continually borne in mind and applied while
welding this material.
Oxidation. Cast iron melts at about 2000° to 2190° F., and
iron oxide melts at about 2450° F. The oxide is formed, however,
at low temperatures, a bright red heat being sufficient to cause
the combination of oxygen from the air with the iron of the casting.
60 OXY-ACETYLENE WELDING
It is not possible to melt this oxide and flow it from the weld, so it
remains in the casting in the form of thin flakes or crust. This
not only prevents the alloying of the molten metal, but also combines
with the free carbon and is, consequently, conducive to the formation
of white iron. Therefore, this oxide must be removed or destroyed.
Expansion and Contraction. Cast iron is absolutely lacking in
elasticity, and its tensile strength is very low. In preparing work
for welding, it is always necessary to take fullest precautions against
the bad effects of expansion and contraction. Expansion and con-
traction should be treated with more importance in the welding of
cast iron than in any other metal.
When the internal strain produced by contraction is greater
than the tensile strength of the section to which it is confined, fail-
ure will occur. When the strain is not great, but still exists, the
resistance of the section to external stresses is reduced in proportion.
Thus a casting may appear to be normal after welding but the
excessive internal strains caused by the welding may make it fail
at the slightest shock.
One of the three general methods of coping with the forces of
expansion and contraction, which are given on pages 36 to 40,
must be used when welding cast iron. The proper method to pursue
is determined by the size and shape of the casting and the nature
and location of the break. A very large percentage of the failures
due to shrinkage cracks may be prevented by an intelligent anticipa-
tion of the forces of expansion and contraction and the proper hand-
ling of the work to overcome these.
Pre=Heating. Pre-heating should be used to some extent in
all cast-iron welding. If the piece is small and the break is so located
that it is not necessary to consider expansion and contraction, the
blowpipe should be played upon it until the chill is removed from
the casting. If the casting is large, an oil or gas burner, or charcoal
fire can be used. In a large casting this preliminary heat treatment
not only favors the execution of a good weld but also requires less
oxygen and acetylene because of this large volume of heat from a
cheap source, thereby reducing the cost of welding.
Welding Rods. The success of cast-iron welding depends
greatly upon the selection of a suitable welding rod. It has been
proved time and again that hard, brittle, and weak welds have been
OXY-ACETYLENE WELDING 61
produced for no other reason than because inferior filling material
was used.
The presence of silicon in proper proportion tends to produce
a soft gray-iron weld. It increases the fluidity of the metal, retards
oxidation, and prevents decarbonization and blowholes. The
success of the filling rod is dependent upon the amount of this ele-
, ment it contains. From 3 to 4 per cent is the average silicon content
of good welding rods. The welding rod must be of high-grade cast
iron, soundly cast and absolutely homogeneous. It must be free from
all sand, grit, and rust. For convenience in handling, it is usually
cast in 24-inch lengths of three diameters, J, f, and | inch. In
case either a longer or heavier rod is desired, two or more are welded
together.
Flux. The principal problem that confronts the welder is to
prevent the formation of oxide, and in case it is formed, to reduce
it and remove it from the weld. If this is not done, the molten
metal will be enclosed in a thin film of nonmetallic material, and
any additional metal that may be fused or added will adhere to this
film rather than break through it and fuse homogeneously with the
other metal. It is not possible to satisfactorily break up this film
mechanically, therefore it must be reduced to a molten, or slag,
condition. To accomplish this a suitable flux is used that will dissolve
the oxide.
A flux is not used solely to dissolve the oxide, but also to float
off other impurities, such as sand, scale, and dirt. It forms a
protecting glaze on the weld and surrounding surfaces and increases
the fluidity of the molten metal.
Borax and salt (sodium chloride) are two compounds often
used by welders, but they really contain little merit as a flux. Their
low fusibility seems to be the only point in favor of their use.
Occasionally, they may be employed to advantage in welding heavy
sections or burned iron, such as are found in firebox and grate cast-
ings, but their function is only that of a cleanser. Both tend to
produce hard iron. There are certain flux powders put on the market
that contain large proportions of manganese. These powders cannot
help but have a hardening effect on the iron. Others contain potas-
sium perchlorate, a violent oxidizing agent. Still others contain
material that chlorinize the weld. Needless to say, powders of this
62 OXY-ACETYLENE WELDING
kind must not be used. It is best to guard against the purchase of
such defective mixtures by obtaining flux powders from reliable
sources.
It is necessary that the welder learn to apply flux properly.
An excess will cause as much trouble as an insufficient quantity.
Blowholes may be increased in size and number by using too much
flux. Also the molten iron will incorporate certain constituents
of the flux if it is applied in excess. The amount to be applied depends
upon the flux used. A welder must learn to know his flux as well
as his blowpipe.
The powder should be applied regularly by dipping the hot
welding rod into it. The quantity adhering is sufficient. Do not
throw large quantites into the weld as plenty will be added by the
welding rod.
Preparation of Welds. All cast iron over J inch in thickness
should be beveled or chamfered before welding. If this is not done,
it is necessary that the metal be burned out by the blowpipe in order
that complete penetration be assured. This is bad practice as it is
almost impossible to do it without either changing the state of the
metal in the groove due to the forced flame, or causing partial ad-
hesion. The chamfering should be a little wider than on other
metals for the reason that it is good practice to introduce as much
special metal from the welding rod as possible.
The chamfering can be done by various means. If the casting
is light and broken in two pieces, it may be taken to an emery wheel
and the edges ground off. If the casting is too heavy to move, a
portable grinder or cold chisel and air or hand hammer can be used.
If the casting is only cracked, the cold chisel and air or hand hammer
are the most satisfactory tools to use.
After the weld has been beveled satisfactorily, the adjacent
metals should be cleaned about \ to \ inch from the edge. This
is important, because all dust, sand, scale, etc., should be removed
from the welding zone.
To Prevent Crack from Extending. If the defect in a casting
is a crack that shows a tendency to extend upon heating, a hole
should be drilled in the casting a short distance from the end and
in the direction the crack would follow. The crack will not extend
beyond this hole, and the hole can be very easily filled in.
OXY-ACETYLENE WELDING 63
Welding Process. Although the melting point of cast iron
is not high, the total heat required to bring it to fusion is great,
therefore a blowpipe of large size is used. The speed of welding
is increased considerably, and the selection of the proper size blow-
pipe is influenced by the extent of the pre-heating.
Cast iron melts very rapidly after the fusing point is once
reached, and when molten is extremely fluid. Because of this
property, the welding should be carried on horizontally, otherwise
the metal will flow toward the lowest point. This is not desired,
because it will tend to produce adhesion. In case it is not possible
to arrange the casting so that the weld will be horizontal, the welding
must be started at the lower end, and skill must be used to prevent
the too rapid advance of the molten metal. It is very difficult to
produce vertical and overhead welds because of the fluidity. In
welding thin sections of cast iron, the rapidity with which it melts
and its fluidity often cause the metal to sink, bulge downward, or
drop in. Consequently, it is necessary that close observation and
careful manipulation be used on this kind of work.
Flame. The incandescent jet of the oxy-acetylene flame should
never impinge on the molten metal. The tip of this jet should be
held at a distance of f to J inch from the metal according to the
thickness. The molten iron is seriously influenced by the high
temperature of this jet and may become oxidized and decarbonized.
This must be rigidly observed except when it is necessary to use
the jet to burn out sand holes, blowholes, etc.
Manipulation of Blowpipes and Welding Rods. Because cast
iron fuses rapidly when once the melting point is approached and
the molten iron is extremely fluid, the circular or oscillating motion
imparted to the blowpipe need not be so pronounced. The welding
of cast iron is nothing but a succession of overlapping miniature
pools, or puddles, of molten metal.
The weld is started by playing the blowpipe on the two lower
edges of the weld. The flame should strike the weld almost perpen-
dicularly, because if the blowpipe is inclined, the flame will blow
the molten metal ahead of the weld, and adhesion will result. When
at the proper temperature, these edges are fused together without
any filling material by the aid of a little flux. It is important
that this first operation be carefully carried out, as the strength of
64
OXY-ACETYLENE WELDING
the weld is dependent upon a good bottom and top. When this
first fusion has been successfully obtained, the welding rod is brought
into play and the high silicon metal is added. With each addition,
Fig. 73. Warm Welding Rod Is Dipped into the
Flux before Each Addition to the Weld
Fig. 74. For Cast-Iron Welding, Blow-
pipe and Welding Rod Are Held Almost
Vertical
the welding rod is previously dipped into the flux can, and the
adhering flux introduced in the weld, Fig. 73. As the welding of
cast iron is a comparatively rapid procedure, the welding rod can
Fig. 75. Dirt May Be Scraped off by Means of the
Welding Rod
Fig. 76. Welding Rod Should Not Be
Held Too Far from Welding Zone.
be held more vertically and added faster, Fig. 74. In welding "dirty"
iron it is sometimes convenient to hold the rod in a horizontal position
and scrape out sand, carbon, or any other dirt by means of the rod
OXY-ACETYLENE WELDING 65
as soon as it appears, Fig. 75. In this connection, it may be added
that the welding rod should be used constantly to work out impurities
and blowholes. The welding rod should be melted as much as possible
in the molten metal of the weld. It should be plunged into this
liquid, and the fusion carried out by playing the flame around it.
The welding rod should not be held too far from the welding zone,
Fig. 76, nor should it be added to the weld drop by drop as shown
in Fig. 77.
As a section of the weld is finished, it should be scraped or rubbed
with a file while red hot, Fig. 78, to remove the film of flux, scale,
sand, and dust that is present. This film if allowed to cool becomes
very hard and is quite resistant to machine tools. Regardless of the
Fig. 77. Welding-Rod Should Not Be Fig. 78. Scraping Finished Weld with File to
Added Drop by Drop Remove Scale
quality of metal beneath it, many welds have been rejected because
of the hardness of this superficial surface.
If the weld is carefully executed and the surface is cleaned,
it will look like the left of Fig. 79, while if poorly executed and not
cleaned, it will look like the right of Fig. 79.
Never go over a weld the second time if it can be avoided. In
case it is absolutely necessary, always add fresh metal from the
welding rod, as a failure to do this will cause a loss of silicon in the
weld and destroy its value to the metal.
Always perform the welding as fast as possible, because extended
heating will tend to lower the silicon content of the weld, with the
resultant formation of hard iron.
66
OXY-ACETYLENE WELDING
Blowholes. Blowholes occur frequently in the weld and are
particularly troublesome if in the bottom of the weld. Their presence
can be caused by mechanically enclosed gases or by improper blow-
pipe handling. When blowholes appear in the weld, they should be
instantly worked out. This may be done by forcing with the welding
rod and applying flux. In beginning a weld, it is necessary that
the presence of blowholes be guarded against, as it is difficult to work
out a blowhole at the bottom of the weld after it is finished. Occasion-
ally, in going over a weld, a blowhole is discovered; this must first be
Fig. 79. Appearance of Cast-Iron Welds That Have Been
Properly (left) and Poorly (right) Executed
burned out by the white jet of the flame and then worked over with
the welding rod.
After- Treatment. The rate of cooling materially influences the
structure of the metal in the weld. If rapid cooling is allowed, hard
brittle iron is produced. If slow cooling is employed, soft gray
iron is formed. Internal strains and stresses may be distributed
and adjusted or, in some cases, eliminated by proper cooling and
annealing.
Castings which are not large or which it has not been necessary
to pre-heat extensively may be satisfactorily annealed by playing
the blowpipe on the weld and surrounding metal until it is at a
bright red heat. The heated portion is then covered with asbestos
OXY-ACETYLENE WELDING 67
paper, cinders, or other nonconducting material that will retain
the heat and protect the castings from air currents. For small
castings, a barrel or bin of hydrated lime and fiber asbestos is recom-
mended. This makes a convenient arrangement and is very satis-
factory as an annealing agent.
Where it is necessary to heat the entire casting in a charcoal
or coke fire, the same temporary furnace used for pre-heating may
be used in annealing. After the welding has been completed, the
casting should be covered over with hot coals and ashes, and the
furnace should be bricked up, i. e., all large air ports closed, the top
covered with asbestos paper, and the casting allowed to cool with
the fire.
The castings should never be removed from the annealing fire
until they are entirely cold. This is imperative, as cold air currents
on the warm castings may cause checks or cracks. In some cases, 12
to 24 hours are required for satisfactory cooling.
Use of Carbon Blocks. In case it is not possible to line up
the weld horizontally, or it is necessary to fill in a wide hole, carbon
blocks or steel plates are sometimes used to dam or retard the flow
of the metal.
MALLEABLE-IRON WELDING
Malleable Iron. Malleable cast iron, or malleable iron, as it
is commonly called, is used extensively in castings where toughness,
malleability, and resistance to sudden shock are required. The
characteristic that gives malleable iron its greatest value as compared
to gray iron is its ability to resist shocks. Malleability in a light
casting, J inch thick and less, means a soft pliable condition and
the ability to withstand considerable distortion without fracture,
while in the heavy section, J inch and over, it means the ability
to resist shock without bending or breaking.
In the manufacture of malleable-iron parts, white iron castings
are packed in annealing pots with suitable material, such as mill-
scale, borings, etc., and subjected to a cherry red heat for from 48
to 96 hours, after which they are allowed to cool slowly. During
this annealing process, the material in which the castings are packed
absorbs the carbon from the surface of the casting. In this way the
surface becomes really a steel, while the inside, or core, becomes
gray cast iron.
68 OXY-ACETYLENE WELDING
Fusion Weld Not Possible. When malleable iron is heated
to a fusing heat the malleable properties are destroyed and cannot
be regained.
Brazing Malleable Iron. The most successful method of joining
malleable iron with the oxy-acetylene blowpipe is by brazing with
Tobin bronze. While this gives a joint of different color, yet the
strength, malleability, and machining qualities are satisfactory.
The two pieces to be joined are beveled as for cast-iron welding.
The edges are brought to a point just below fusion, great care being
taken that they do not become fused. When the edges are at the
right temperature, a rod of Tobin bronze is fused into the groove
with the aid of a good brass flux. The work should be carried out by
using a flame having a slight excess of acetylene and should be done
as rapidly as possible to prevent oxidation of the bronze.
ALUMINUM WELDING
General Considerations. When aluminum approaches its melt-
ing point, it does not change color in ordinary light, but retains its
silvery appearance even when in the molten condition. When
molten, it is very fluid and is, therefore, rather difficult to control
under the welding flame.
Oxidation. Aluminum oxidizes very easily when in a molten
condition, forming an oxide that melts at about 5400° F. The oxide,
therefore, cannot be penetrated by means of the flame, but must
be removed either chemically by means of a flux or mechanically
by means of a paddle.
Expansion and Contraction. Because of the high heat con-
ductivity of aluminum, expansion and contraction do not give great
difficulty owing to localized heating. However, because aluminum
expands greatly and is very weak when at high temperatures, con-
traction strains are very likely to produce cracks or checks unless
the work is allowed to cool evenly and slowly. It is advisable to
pre-heat aluminum castings to between 300° and 400° F. to aid the
distribution of the heat and prevent warping.
Welding Rod. In welding sheet aluminum, such as automobile
bodies, the welding rod should be clean material of the same alloy
as the sheets that are being welded. If wire cannot be obtained
of the same composition as the sheets, narrow strips should be
OXY-ACETYLENE WELDING 69
sheared from the sheets themselves and used for a filling material.
The strips should be sheared about as wide as the sheets are thick.
For aluminum castings, such as crank cases, a good grade of
aluminum wire about J inch in diameter should be obtainecj. Welders
should not use the cheap solders or very low fusing cast rods that
are sometimes sold, and for which great claims are made. The
operator will readily appreciate that when these materials are added
to the weld they will merely adhere to the sides, because, while the
filling material will be quite fluid, the edges of the weld will not be at
a fusing temperature.
Flux. It is impossible to weld sheet aluminum without the
use of a good flux to dissolve the oxide and float it to the top as a
slag. In cast-aluminum work a paddle may be used to accomplish this
result, but such a device is not practical for sheet work. The flux
may be applied either by dipping the warm welding rod into the
flux powder or by mixing the flux with water to form a paste and
applying this to the joints by means of a brush. Care must be taken
that too much flux is not used, because an excess will produce a
porous weld and one with a poor surface. After the work has been
completed the flux should all be washed off with warm water.
Flame. In order to be sure that an oxidizing flame is not
being used, it is permissible and advisable to use a flame showing
a slight excess of acetylene. This flame will also have the advantages
of being slightly larger in volume than the neutral flame and of lower
temperature, this last feature being helpful, especially to the new
operator.
Sheet=Aluminum Welding
Sheet-aluminum work may be handled very similarly to sheet
steel as regards preparation and allowance for expansion and
contraction.
Types of Joints. For light sheets under ^ inch the flange
weld should be used. The butt joint may be successfully made on
light sheets by an experienced operator, but there is a great deal
of danger of burning through and having to fill up holes, which will
leave a poorly finished weld.
For sheets above YS mcn the butt weld is found to be the best,
and for sheets above f inch the edges should be beveled the same
as for steel plates.
70 OXY-ACETYLENE WELDING
Welding Process. Select the proper size blowpipe and welding
rod, a good flux, and arrange the work for welding. Start the welding
by playing the secondary flame of the blowpipe over the parts
surrounding the weld, to warm them up slightly. If the flux is to
be applied with a brush, it should be done at this time, because the
heat will evaporate the water and leave the solid flux evenly dis-
tributed over the weld. Welding should then be started from J to 1
inch from the end — not at the end. The blow pipe should be handled
about the same as for steel welding, care being taken that the inner
cone of the flame does not come in contact with the metal. For
very thin sheet welding it is not necessary to give the circular or
oscillating motion to the blowpipe; it is merely necessary to move
it forward in a straight line.
On the heavier work, however, the same motions should be
used by the welding operator as are used for steel. The welding
wire is best held directly in line with the weld and always in contact
with the metal just ahead of the blowpipe. If the wire is not in con-
tact with the edges when they become molten, they will be likely
to curl up or draw away instead of flowing together. After the
main weld has been completed, the operator should go back and
weld the short section that was left unwelded at the very beginning.
After the work has cooled the flux should be removed by washing
off with warm water.
Re-Welding. The operator should be careful that the weld is
completed as he goes along, so that he will not have to go back to
make repairs or to do re-welding. If it is necessary to go back over
a weld, cracks or checks are very likely to result because of the
weak condition of the metal when it is at a fusing temperature. If
it is necessary to re-weld a certain portion of the joint, the surface
should be chipped off so as to present a clean surface for the new
filling material to fuse to. Following the suggestions already made,
the seam and the surrounding surfaces should be thoroughly pre-
heated before the welding is started to prevent cracking as much
as possible.
After- Treatment. If possible, welds in aluminum sheet should
be reheated evenly to equalize any internal strains. Then, after the
weld has become cold, it should be hammered to improve the grain
of the metal.
OXY-ACETYLENE WELDING 71
Cast Aluminum Welding
Aluminum Castings. Most aluminum castings are alloys of
aluminum, zinc, and copper; the alloy being added to the aluminum
to give it a higher tensile strength and increase its resistance to
shock. The welding of cast aluminum is different from that of
sheet aluminum and resembles in a general way the welding of
cast iron. Oxidation is taken care of by using flux or by scraping the
oxide out by means of a paddle. The second method is faster and
is the one preferred by most operators.
Paddle. The paddle is made by flattening down the end of a
J-inch steel rod to a smooth short flat blade about f inch wide.
The handle may be left straight or bent to suit the operator. The
paddle should be used only when just below a red heat. If it is
cold, the molten metal will stick to it, and if it is too hot it will burn
and the metal will stick to the roughened surfaces.
Preparation. Sections if over J inch in thickness should be
chamfered before the welding is started. Sections thinner than
this may be worked without beveling. The old metal may be scraped
out by means of the paddle in order to give a clean bright surface
for the new material to be added to.
Pre=Heating. Because aluminum alloy castings are not very
ductile and are weak when at a high temperature, expansion and
contraction must be taken care of. This is handled in the same
general way as in the case of cast-iron work. The casting should
be pre-heated either partially or wholly by some slow heating agent,
such as a gas burner or mild charcoal fire. The pre-heating should
never be carried to too high a temperature, because of the danger
of the metal sinking, or caving in. The casting will be sufficiently
warm for welding when a file or chisel will mark it easily, or when
a piece of dry pine stick is charred upon being drawn across the
heated section.
Welding Process. When a flux is used in welding cast alumi-
num, the work is carried on in the same general manner as in welding
cast iron, and the same general precautions regarding the peculiari-
ties of the metal are to be observed as in welding sheet aluminum.
If a paddle is used to break the film of oxide and scrape it out of
the weld, the edges are brought to a state of fusion for a length of
about 1 or 1 J inches. The paddle is then used to scrape out the weld
72 OXY-ACETYLENE WELDING
to make a slight bevel and present clean surfaces for the filling mate-
rial to be added to. The welding rod is then introduced into this
groove. The paddle is used continually to work in the filling material,
scrape off any oxide that forms, and then to smooth off the surface
of the weld. After a small section of the joint has been completed,
the casting is turned over, and the weld for this length is smoothed off
on the underside by means of the blowpipe and paddle. The welding
is carried on in this manner, section by section, until the entire joint
is completed. If the weld were completed on the first side and then
turned over and smoothed its entire length on the underside, cracks
would develop, and the casting would warp out of shape.
After=Treatment. When the welding has been completed, the
casting should be reheated slightly to remove any local strains and
should then be covered over with asbestos paper to protect it from
drafts and to allow it to cool very slowly. If the cooling is carried on
rapidly, or if air currents are allowed to strike the casting, it will very
likely crack either in the weld or some weak section.
COPPER WELDING
General Considerations. Because of the high thermal
conductivity of copper, the heat from the blowpipe is conducted
back into the work rapidly and is lost to the weld. This necessitates
the use of a large size welding head or the use of an auxiliary source
of heat to assist the welding flame in the case of heavy work. When
at high temperatures, copper is weak in tensile strength the same
as aluminum. Because of these two factors the effects of expansion
and contraction must be carefully considered, so that the work will
not cool too rapidly after the welding has been completed, and will
not crack at high temperatures.
Oxidation. Copper oxidizes quite readily, forming an oxide
which dissolves in the molten metal and changes the structure of
the weld. The amount of oxide that can be absorbed is very high,
consequently great care must be exercised to keep the absorption
at a minimum. Welding rods containing a small percentage of
phosphorus and suitable fluxes are used to counteract the oxide and
reduce it as much as possible.
Welding Rod. For successful copper welding, it is necessary
to use electrolytic copper containing about one per cent phosphorus,
OXY-ACETYLENE WELDING 73
supplied in coils and drawn rods. The cast copper alloy rods that
are on the market are not satisfactory, because the structure and
composition will vary even in a single rod to such an extent that a
homogeneous weld cannot be made.
Flux. In welding copper the flux is used not only to cleanse
the weld, but also to protect the metal adjacent to the welding zone
from the gases of the flame. When welding sheet copper it is advisable
to make a paste of the flux by adding water and to coat the metal
about one inch adjacent to the edge of the weld. When this flux is
melted, it will form a glassy film that will protect the metal from the
gases of the flame and the air surrounding the work. Additional
flux is added to the weld as the work progresses, by dipping the
warm rod into the dry flux, as in welding other materials.
Flame. It is very important that the neutral flame be
maintained at all times, and the operator should use great care in
adjusting his gases, so the flame will not have an excess of acetylene
nor be oxidizing. Because of the peculiar properties of the metal,
the gases of the reducing flame are very likely to be absorbed, and
because of the ease with which the metal oxidizes, oxidation is
liable to occur if the flame contains an excess of oxygen.
Preparation. Sheets that are less than J inch in thickness
may be butted together without beveling. Sheets heavier than
this should always be beveled, and no attempt should be made
to depend upon the flame to penetrate the heavier thicknesses. In
all cases of copper welding, the edges to be joined and the material
adjacent to the edges should be scraped or filed to present a clean
surface for the filling material to be added to.
Welding. The edges of the metal surrounding the weld should
be raised to a fairly high temperature before the actual welding is
started. On small pieces and light-weight work, this may be done
by means of the welding blowpipe, but for heavy work and long
welds, it is best to do this by means of a gas or oil pre-heating burner.
After the work has been brought to a high temperature, the welding
should be started at one end and should be performed as rapidly
as possible. The welding rod and edges of the weld should reach
the state of fusion at the same time, so as to prevent adhesion and
to insure a good weld. This feature is harder to accomplish in welding
copper than in other metal, because the heat is conducted back into
74 OXY-ACETYLENE WELDING
the rod or into the work very rapidly, necessitating very careful
and skillful manipulation of the blowpipe and rod. The blowpipe
should be held almost vertical, about the same as in the case of
cast-iron welding. If held at too great an angle, the molten metal
will be blown ahead and will adhere to the cold edges of the weld
in advance of the blowpipe. The inner cone of the flame should
never come in contact with the metal, but should be held about
J or 1 inch above the surface of the weld to prevent burning the
metal. The oscillating motion should be carried on about the same
as in steel welding but a little more rapidly, and should consist of
smaller circles. The welding rod should be plunged into the molten
metal all the time and should be continuously moved around or
stirred, so that it will be thoroughly incorporated and will bring the
oxide and slag to the surface. The weld should be built up above
the surface of the sheets, so there will be enough material to allow
for hammering after the welding has been completed..
Re-Welding. In case it is necessary to re-weld a portion of the
joint, it is necessary that the old material be chipped out and new
material added.
After=Treatment. After the welding operation has been
completed, the work should be heated very carefully and evenly
until it is almost at a bright red heat. The weld should then be
hammered while hot, so that the strength of the joint will be increased
as much as possible. After the hammering has been finished, the
work should be again reheated to a red heat and cooled quickly
by means of an air blast or chilled by plunging in water. Care must
be exercised in this operation if the work be a casting having confined,
or rigid members, so that .cracking, or checking, does not occur.
BRASS AND BRONZE WELDING
General Considerations. Brass and bronze are both alloys of
copper, brass consisting mainly of copper and zinc, and bronze
of copper and tin. Both brass and bronze are welded in about the
same general manner as copper, but because of the peculiar properties
of the alloying metals, zinc and tin, it is necessary that they receive
certain variations in welding.
Oxidation. In both brass and bronze, the alloying metal is
greatly affected by the high temperature of the flame, and the material
OXY-ACETYLENE WELDING 75
will be subject to a loss of zinc or tin, unless proper precautions are
taken. These metals will combine with the oxygen and pass off as
white vapor, and leave a weld of different composition and color.
Absorption of Gases. The molten metal in both brass and bronze
absorbs certain gases very readily, and unless this absorption is
counteracted, the weld will be spongy and weak. This may be taken
care of by using a suitable welding rod and flux.
Welding Rod. Because of the varying composition of brass
and bronze, and because of the loss of the alloying elements when
welding, it is practically impossible to produce welds of the same
color as the original material. When welding brass, a good grade
of drawn brass will be found most satisfactory, and in the case of
bronze, a good drawn bronze, such as manganese or Tobin bronze.
The cast rods that are on the market are not satisfactory, because it is
quite impossible to cast a rod having the same composition throughout.
Flux. The flux used for brass and bronze is practically the
same as that used for copper. It should be applied by dipping the
warm welding rod into the powder and adding it to the weld in this
manner. It is not necessary to use as much flux as in welding pure
copper, and care must be taken that an excess is not used, because the
weld may become porous.
Flame. A neutral flame must be maintained at all times for
the same reasons as explained under copper welding. The blowpipe
should be held between J to J inch from the metal. If the flame
is held too close in the case of bronzes, the concentrated heat will
cause a segregation or separation of the tin from the copper, and
it will be practically impossible to again unite these elements.
Preparation. The edges of the metal for a thickness of less
than | inch may be merely butted together and welded, while for
metals above this thickness the edges should be beveled or cham-
fered, so as to allow penetration of the flame and insure a good weld.
Welding. Because of the high conductivity of these materials,
it is best that they be pre-heated to bring them to a suitable condition
for rapid welding. Care must be taken when pre-heating bronze
that it does not get too hot, because it is weak at high temperatures
and is liable to break or crack under its own weight. The
welding is carried on in about the same manner as for copper, and
the blowpipe is handled in practically the same way. The welding
76
OXY-ACETYLENE WELDING
rod should be in contact with the edges of the metal at all times,
and the blowpipe should be played constantly on both the rod and
the edges of the metal to keep them at the same temperature in order
that adhesion may be prevented.
Re-Welding. Re-welding should be avoided, but if it is
absolutely necessary to re-weld the work, the section should be
chipped out, and new material added, as in the case of copper.
After=Treatment. Both brass and bronze should be annealed
after welding by reheating evenly, and then allowed to cool slowly.
Brass may be improved by hammering before the final annealing.
Brass of low zinc content, i.e., red brass, should be hammered
while hot, while brass of high zinc content, i.e., yellow brass,
should be hammered cold.
MISCELLANEOUS PROCESSES
CUTTING
Cutting In Automobile Repairs. The oxy-acetylene cutting
blowpipe finds considerable application in the automobile repair
shop for beveling the ends of shafts
and other pieces of work preparatory
Fig. 80. Beveling Round Shaft for Welding.
The other piece is on the table
Fig. 81. Beveling End of Heavy
Square Shaft for Welding
to welding, Figs. 80 and 81, cutting reinforcing plates out of large
sheets for frame repairs, altering chassis, etc., Fig. 82. The cutting
OXY-ACETYLENE WELDING
77
blowpipe is capable of doing this work cheaply and quickly, two
necessary factors for the successful first-class repair shop.
Principle of Cutting with Oxygen. At ordinary temperatures,
steel oxidizes in the air, forming what is commonly called "rust".
At a white heat it will oxidize more rapidly, as is seen in the black-
smith shop when pieces are brought to a very high temperature.
When steel is heated to a red heat, and
a stream of pure oxygen is directed on
it, the oxidation takes place more rap-
idly and more violently and is restricted
to the locality upon which the stream
of oxygen is played. This localized oxi-
dation is the basis upon which the oxy-
acetylene cutting blowpipe operates.
Metals That Can Be Cut. Steel and
wrought iron are the only metals that
can be cut successfully by means of
the oxygen jet. Although cast iron, cop-
per, brass, bronze, aluminum, etc., oxi-
dize easily, nevertheless they cannot
be cut.
When the oxygen combines with
the iron, heat is generated. This heat
of formation, with the aid of the heat
supplied by the pre-heating flames of
the blowpipe, brings the oxide to a molten condition. The molten
oxide either flows or is blown out of the cut and leaves a fresh
thoroughly heated line through the metal for the further action
of the cutting oxygen. In the case of steel and wrought iron, the
oxide melts at a much lower temperature than the material being
cut and therefore blows out without melting the surface of the
material. In the cases of cast iron and certain alloy steels, the
melting temperature of the oxide is as high and in some cases
higher than that of the metal, and therefore melts the edges or
freezes in the kurf and so hinders the cutting. Also, in the case
of some of these materials, the heat of formation produced by the
combination of the oxygen with the metal is not sufficient to carry
the cut through the thickness of the work.
Fig . 82 . Cutting Reinforcing Plate
Out of Large Sheet Steel for
Frame Repair
78
OXY-ACETYLENE WELDING
Necessary Cutting Apparatus. A complete cutting station,
Fig. 83, consists of the following apparatus:
Cutting blowpipe with set of cutting nozzles
Oxygen cutting regulator with two gages
Acetylene regulator with one or two gages
Adapter for acetylene cylinder
One length high-pressure rubber hose for acetylene
One length copper armoured hose for oxygen
Darkened spectacles, wrenches, hose clamps, etc.
Cutting Blowpipe.
In the cutting blowpipe,
Fig. 9, page 9, there
are usually six small
oxy-acetylene flames sur-
rounding a center orifice
through which pure oxy-
gen is directed. The six
heating jets are used
only for the purpose of
bringing the edge of the
material to a tempera-
ture at which the jet of
pure oxygen will unite
rapidly with the steel,
as explained above.
Cutting Nozzle.
There are usually four
sizes of cutting nozzles
furnished for handling
work of various thick-
nesses, from very thin
plate up to material 14
and 16 inches thick.
Besides these, some
manufacturers also fur-
nish what is known as
a "rivet cutting nozzle".
This is a thin flat nozzle that can be laid against the sheet, allowing,
the rivet head to be cut off close to the sheet.
Fig. 83. Cutting Unit for Use with Acetylene in Cylinders,
Mounted on Emergency Truck
Courtesy of Oxweld- Acetylene Company, Chicago
OXY-ACETYLENE WELDING 79
Working Pressure. The necessary pressures of the gas that are
required by the different sizes of cutting nozzles and for the different
thicknesses of material are given by the manufacturers. It is very
important that the operator use these pressures instead of higher
pressures because of the increased amount of oxygen used and the
consequent high cost of operation, also because the cut will not be
smooth if too much oxygen is used.
Care of Blowpipe. If the blowpipe is handled properly there
will be very little deterioration. It should only be necessary to
clean the replaceable and working parts, repack the valves, and
occasionally ream out and true up the nozzles. Care should be taken
that the orifices of the nozzles do not become enlarged by reaming,
because the heating jets will be made thicker and shorter and the
cutting jet will spread rather than leave the blowpipe as a long
thin stream.
The blowpipe may be cleaned the same as the welding blow-
pipe by removing both the acetylene and oxygen hose and connecting
the nozzle to the oxygen hose, Fig. 16, page 18, and turning on the
oxygen to a pressure of about 20 pounds per square inch, having
first the cutting oxygen valve open, then the acetylene needle valve,
and lastly the oxygen needle valve. This will allow the large particles
to be blown out of the larger passages before they have a chance
to clog up the smaller passages.
Regulators. The cutting regulator, in principle, is the same as
that described on page 20, but in size it is much larger than the
welding regulator and is capable of both a higher delivery pressure
and a greater volume.
The acetylene regulator is the same as is used in the welding
equipment, and described on page 20.
Care of Apparatus. The blowpipe, regulators, and hose should
receive the same care and attention as is explained for the welding
apparatus on pages 18 to 21.
Instructions for Connecting Apparatus. The regulators and the
blowpipe are connected up in the same manner as the welding
apparatus, and therefore the operator is referred to pages 22 to 23
for instructions.
How To Light the Blowpipe. (1) Take the blowpipe in hand
and open the oxygen cutting valve fully.
80 OXY-ACETYLENE WELDING
(2) Turn the oxygen pressure-adjusting screw to the right
until the required pressure for the work to be done shows on the
low-pressure gage. (See the maker's chart for the correct pressure.)
(3) Close the oxygen cutting valve.
(4) Open the acetylene needle valve fully.
(5) Turn the acetylene pressure-adjusting screw to the right
until a good jet of acetylene issues from the heating orifices. In
the case of pressure blowpipes, until the required pressure for the
thickness to be cut shows on the low-pressure gage. (See the maker's
chart for the correct pressure.)
6. Open the oxygen needle valve one-quarter turn and light
the blowpipe by means of the pyro-lighter that is usually furnished.
NOTE — A back-fire might occur if there is not enough acetylene being
supplied. If this occurs increase the acetylene supply by turning the acetylene
pressure-adjusting screw farther to the right.
7. Adjust the acetylene pressure-adjusting screw to give a
slight excess of acetylene to the -flame.
8. Adjust the acetylene needle valve to give a neutral flame
(see under Flame Regulation, page 25) when the cutting oxygen
valve is open.
To Shut off the Blowpipe. In the case of the injector type of
blowpipe, first close the acetylene needle valve and then the oxygen
needle valve.
In the case of pressure blowpipes, first close the oxygen needle
valve and then the acetylene needle valve.
To Cut. With the cutting valve closed apply the heating flames
to the edge of the metal, keeping the nozzle at such a distance that
the small flames barely touch the metal. As soon as the metal
becomes heated to a cherry red, open the cutting valve, raise the
blowpipe slightly to increase the distance between the nozzle and
metal, and then move it along the surface as fast as a distinct and
and clear kurf can be secured. The blowpipe should be held at a
constant distance from the work. It should travel away from the
operator in order that he may watch the cut advance.
Back=Firing. Occasionally, particles of molten metal will
impinge on the nozzle of the blowpipe, or the operator will allow
the nozzle to touch the surface of the metal, and the blowpipe will
back-fire. When this occurs, first close the acetylene needle valve
OXY-ACETYLENE WELDING 81
and allow oxygen to clear the passage, then open the acetylene
needle valve fully and relight. If the back-firing continues, close
both the acetylene and oxygen needle valves, cool the blowpipe by
plunging in water and relight. Other causes of back-firing are
loose internal and external nozzles or dirt on the nozzle seat. These
can be eliminated by tightening the nozzles and cleaning the seat.
These back-fires are usually only a series of pops or sharp reports,
and, as a rule, will not extinguish the flame.
Notes on Cutting. Heating Flames. The heating flames
should be small to produce smooth cutting. If the flames are too
small, the blowpipe is liable to back-fire. If they are large, the top
edges of the cut will melt and produce a rough cut.
Speed of Cutting. The speed of the blowpipe travel should be
slow enough to allow the oxygen jet to penetrate yet not so slow
that the oxygen will be wasted.
Restarting Cut. If the blowpipe travels too fast, and the cut
is "lost", it is necessary to shut off the cutting oxygen and apply the
heating flames to the point of stopping until the metal is hot enough
to start the cut again.
To Cut Round Shafts, Etc. The cutting of round pieces will
be made easier if the surface of the work is first chipped with a chisel.
This will present a good edge for the cutting blowpipe to bite on.
To Pierce Holes. When piercing holes, a high oxygen pressure
is necessary, and the metal must be brought to fusion before the
cutting oxygen is employed. The blowpipe is held at a slight angle so
the sparks will be blown out of the hole and away from the blowpipe.
Cutting Dirty and Poor Material. If there is considerable rust,
scale, paint, etc., on the surface, the cutting will be interfered with
by small particles flying against the end of the nozzle and perhaps
causing back-firing. To overcome this, the heating flames may be
made longer, allowing the blowpipe to be held farther away from
the surface, or the scale or paint may be removed by first passing
the flame over the line of cutting before the cutting is started.
LEAD BURNING
Different Methods. Formerly, lead burning, or lead welding,
was confined to garages and service stations that catered to the electric
automobile only, but since the introduction of electric lighting and
82
OXY-ACETYLENE WELDING
starting batteries for gasoline automobiles, lead burning has become
one of the works of the repair man in all garages. It is therefore
important that the repair man have a sufficient knowledge of this
class of work to enable him to handle any work of this nature that
may happen to come into his shop.
Up to the time of the recent development of a very small oxy-
acetylene blowpipe for lead-burning work, the hydrogen air burner
was used by most lead burners. The oxy-acetylene blowpipe, how-
Fig. 84. Oxy-Acetylene Lead Burning Apparatus
Courtesy of Oxweld Acetylene Company, Chicago
ever, is rapidly supplanting the old method and, as a matter of fact,
within two years it has become universally accepted as being far
superior to the old method in handiness of operation, speed, and
consequent economy, and has been adopted by the large battery
makers in both their factories and service stations.
When an operator accustomed to the old flame tries the oxy-
acetylene blowpipe, he is very likely to discredit it at first and claim
that it is not satisfactory. However, every operator who gives the
oxy-acetylene lead-burning blowpipe a fair trial and uses it in
accordance with the methods recommended by the manufacturers
OXY-ACETYLENE WELDING 83
of the apparatus must acknowledge it as being superior to any
method he has ever used. Its advantages are emphasized even more
emphatically if he returns to the old, slower, and more costly methods.
Lead=Burning Apparatus. A complete lead-burning station
for use with oxygen and acetylene, Fig. 84, consists of the following
apparatus :
Lead-burning blowpipe with set of tips
Oxygen regulator with low-pressure gage
Acetylene regulator with low-pressure gage
Adapter for acetylene cylinder
Valve-block
Two lengths of high-pressure hose to connect regulators to valve block
Two lengths of small hose to connect blowpipe to valve block
Lead-Burning Blowpipe. To make the blowpipe as light in
weight and as handy as possible there are no large valves. Instead,
a valve block is furnished for regulating the gases, which may be
attached to a bench or a wall. In order to make minor or finer
adjustments of the flame, and to allow various size tips to be used
on the blowpipe and still maintain a perfect flame, an adjustable
injector is provided at the top of the blowpipe within reach of the
operator's fingers.
Tips. There are about five sizes of tips supplied for use on
different thicknesses and various classes of work, each giving its
own special size flame. The oxygen consumption of the various
size tips ranges from | to 6 cubic feet per hour. For storage-battery
work the average consumption is about 2 cubic feet per hour.
Regulators. The regulators supplied with lead-burning apparatus
operate on the same principle as the regulator described on page 19,
the only difference being that they are of smaller size and especially
adapted to small flames.
Operation of Lead=Burning Apparatus. The apparatus is
connected in the same general manner as the welding apparatus
for which instructions are given on pages 22 to 26. The needle
valves on the valve block are used to obtain approximate adjust-
ment of the flame, and then the small thumb-nut on the blowpipe
is used to make the finer adjustment. The pressure-adjusting
screws should be set to give pressures of about 10 pounds per
square inch for the oxygen, and 2 pounds per square inch for
the acetylene.
84
OXY-ACETYLENE WELDING
The blowpipe, regulators, hose, etc., should receive the same care
and attention as the welding apparatus and for which suggestions
are given on pages 18 to 21.
Lead=Burning Process. The oxy-acetylene blowpipe should be
handled in such a manner that the flame strikes the work perpen-
dicularly. If the blowpipe is used on a slant, the inner cone will
not bring the work to the fusing temperature as rapidly as if held
vertically, and the secondary flame, or outer envelope, will be very
likely to heat the surrounding metal to such a temperature that it
will give way and break under its own weight. When working with
the oxy-acetylene flame on stor-
age batteries and the like, the
operator should do the burning
quickly. He should bring the
flame down to the work, fuse the
metal, add the necessary burn-
ing bar, or filling wire, smooth
off the work, and remove the
flame, all as rapidly as possible.
Burning Terminal Groups.
When burning plates to terminal
bars, a small flame should be
used, and the work should be
held in a fixture, as shown in
Fig. 85. The small ends on the
plates should extend up into the
terminal bar slots about two-
thirds of the way. The burning should be carried on by first fusing
the ends of the plates to the bottom of the slots, then filling up the
rest of the slot by adding lead from a coil of wire or a burning bar.
After the several plates have been burned on in this way, the flame
should be moved perpendicularly over the surface to smooth it off
and leave a nice finish. The flame should not be held flat against
the work. It will take longer to smooth off the work, and it will
not have nearly as neat an appearance if the flame is used flat.
Burning-On Connecting Links. The terminal poles should
extend up into the links about one-third of the way. The flame
should be brought down into the hole until the inner cone almost
Fig. 85. Assembling Terminal Groups
OXY-ACETYLENE WELDING
85
touches the top of the pole, and the pole fused and united with the
bottom of the link as quickly as possible. After a good union has
been secured in this manner, the burning bar should be introduced
and the rest of the cavity filled up, Fig. 86. When working on links
and poles it is advisable to do only part of one pole, move to another
for a few minutes, and then come back to the first for a few minutes.
This will allow the work to cool off slightly and will prevent breaking
down or melting away. When burning this class of work, especially
if the lead is old and pitted with dirt and cut by acid, it is advisable
to increase the supply of oxygen
and use an oxidizing flame
when working down in the
pocket. This will burn out any
dirt and will prevent the blow-
pipe from puffing out when it is
burning in the rare atmosphere
that exists in the pocket.
Forms or Molds. Small steel
frames, or molds, are found very
convenient, e s p e ci a 1 1 y when
working on terminal links.
These molds are shaped to con-
form to the work and are placed
around it while burning. They
are a great help in preventing the
corners of the work from break-
ing down and melting away and, in this manner, relieve some of
the tediousness of the work and allow the operator to work under less
strain, and permit the work to be done by men who are not skilled
lead burners, but who have occasional work of this sort to do.
Fig. 86. Burning-On Connecting T.inlp*
CARBON REMOVING BY USE OF OXYGEN
Methods. Old Process. Up to within the last few years
the methods used for removing the carbon from gas-engine cyl-
inders were very impractical and unsatisfactory. To do this work
meant the dismantling of the motor, the removal of all the parts,
and the scraping of the cylinder walls by hand. Because this
86
OXY-ACETYLENE WELDING
operation necessitated a great deal of work it was not done, in most
cases, until the carbon deposit became very heavy.
Oxygen Process. The introduction of the inexpensive process
of removing the carbon by burning it out by means of pure oxygen
has replaced the old methods and they are no longer used. This
new process is so simple, necessitates so little work, can be done so
quickly and cheaply, that it can be employed every few months and,
in that way, keep the cylinders free from carbon.
Carbon=Removing Apparatus. Complete apparatus for remov-
ing carbon by means of oxygen, Fig. 87, consists of the following:
Carbon-removing handle with flexible tube
Oxygen regulator with low-pressure gage
One length of high-pressure rubber hose
It will be seen from this list that all that
is necessary for a garage to have in addition
to its welding equipment is the carbon-
removing handle with a flexible tube.
Burning Out Carbon. Shut off the gas-
oline at the tank or just in front of the
carburetor and allow the engine to run until
it has sucked the gasoline out of the lines.
Remove the valve caps and spark plugs
from all the cylinders.
Turn the engine over by hand until
the first piston is at the upper end of its
stroke and both its valves are closed. Intro-
duce a/ small quantity of kerosene into the
cylinder head by means of an oil can or a
piece of saturated waste. Light the kero-
sene in the cylinder, introduce the end of
the flexible tube into the cylinder and allow the oxygen to play
on the carbon at a pressure of about 5 pounds per square inch.
The carbon deposit will catch fire and will continue to burn as
long as there is carbon present. Of course, if the carbon is depos-
ited in patches it will be necessary, after one patch has been
removed, to start another by means of kerosene.
After the first cylinder has been thoroughly cleaned, turn the
engine over by hand until the piston of the second cylinder is at
Fig. 87. Carbon-Removing
Apparatus
OXY-ACETYLENE WELDING 87
its upper stroke with its valves closed, and then proceed to remove
the carbon from this cylinder in the same manner.
After all the cylinders have been thoroughly cleaned, clean the
valve caps and spark plugs by scraping or by burning off the carbon
and then replace them in the engine.
Notes on Carbon Burning. Before burning out the carbon be
sure that there is no chance of gasoline being present which might
cause back-firing into the intake manifold.
The oxygen pressure should not be too high. Only enough oxygen
should be supplied to keep the carbon kindled. Too much pressure
will waste oxygen and increase the cost of burning out the carbon.
Too much kerosene must not be used, because there is a chance
of the operator burning his hands with the sudden burst of flame
that might result.
EXAMPLES OF AUTOMOBILE REPAIR
Pressed=Steel Parts. All pressed-steel parts of automobiles,
such as frames, bodies, fenders, axle housings, tubing, etc., should
be welded, using a pure iron welding wire for a filling material.
Frames. Almost all frame repairs necessitate a certain amount
of dismantling of other parts. The extent of the dismantling depends
upon the location of the proposed weld. If the work is to be done
under the body, it is best to remove the car body. This is not
absolutely necessary, however, because the work can be done by
merely jacking up the body several inches to give enough room to
do the work, and protect the body from the heat of the welding
flame. If the weld is to be done close to the radiator, this should
be removed so that the solder will not be melted out, Fig. 88. If
the weld is about 12 inches from the radiator, the solder can be
protected by placing sheet asbestos over the radiator. In this
connection it is well to remind the operator that it is always advisable
to cover the parts of the car near the welding with sheet asbestos
to protect them from any possibility of the flame or heat getting
too close.
Jacks should be placed under the frame and the frame brought
into alignment before the welding is started; the jacks should not
be removed until the weld has been completed and has become
thoroughly cooled.
88 OXY-ACETYLENE WELDING
It is always advisable to bevel the work by chipping. In the
case of frames of light-weight pleasure cars this may be dispensed
with if the operator is careful to penetrate through the thickness
of the material. All paint, dirt, and grease must be scraped off
next to the weld from both the inside and outside of the frame
before the welding is commenced, to prevent dirt from being
incorporated in the weld.
A reinforcing plate should be prepared about the same thickness
as the frame, as wide as the frame is high, and about three times
Fig. 88. Radiator Is Removed if Welding Flame Is Near It
as long as it is wide. This may be cut out of sheet steel by means
of the cutting blowpipe, Fig. 82, page 77, or by means of a hack saw.
The blowpipe is the quickest and easiest method, especially for
cutting plates for curved frames such as are used on pleasure cars.
The weld will look better if the reinforcing plate is welded on the
inside of the frame, but in some cases that is impossible without a
great deal of extra dismantling. It is then allowable to weld it on
the outside.
The welding should start at the lower end of the frame and
move upward as explained under Vertical Welding, page 31. The
OXY-ACETYLENE WELDING
89
two flanges of the channel should then be welded, starting at the
corner and moving toward the edge. When welding the lower
•••••I
Fig. 89. Badly Bent Frame
Fig. 90. Frame after Heating with Welding Flame and Straightening
90
OXY-ACETYLENE WELDING
flange, the work should be carried on as explained under Overhead
Welding, page 31. After the frame has been welded, the reinforcing
plate should be welded on by welding the horizontal edges first
and the ends last.
The weld will be materially strengthened if it is hammered
during the process of welding, as explained under Hammering,
page 46.
The oxy-acetylene blowpipe is also very valuable in straightening
frames that have become bent in
accidents. A frame of this sort
is shown before and after straight-
ening in Figs. 89 and 90.
Bodies and Fenders. Bodies
and fenders that have been torn
can be successfully welded if the
operator uses his best efforts and
is careful.
Fenders, as a rule, do not
present very much difficulty be-
cause the break usually extends
to the edge. It is advisable to
pack wet asbestos along both
sides of the weld to prevent buck-
ling as much as possible, Fig. 91.
The wet asbestos will absorb the
heat and will not allow it to be
conducted back into the sheet.
Bodies should be welded in a similar manner when they are
torn. If possible, it is advisable to bend the edges outward slightly
before welding. Then, as the weld is cooling, hammer it flat to
compensate for the contraction that takes place.
If a patch must be welded in, it should be prepared either
round or oval, or should have rounded corners of large radii.
The patch should be dished to compensate for the contraction
that will take place when the work cools. The hole in the body
and the patch should be trimmed so as to fit well. When
the patch is ready, it should be tacked in place. The welding
should be carried on as quickly as possible. After the weld has
Fig. 91. Welding
along Weld Will Prevent Buckling
Torn Fender. Wet Asbestos
Will Prevent .
of Light Sheets
OXY-ACETYLENE WELDING
91
been completed, the flame should be played on it to heat it evenly.
As the weld starts to cool, the center of the patch should be heated
Fig. 92. Broken Front Axle
Fig. 93. Welded Front Axle
Fig. 94. Crankshaft in Crankshaft Jig Table for Welding
slightly so that it will stretch easily and compensate for the con-
traction taking place in the weld.
92
OXY-ACETYLENE WELDING
Springs. The welding of springs should not be attempted
except for emergency repairs to allow the car to be used until a new
spring can be obtained. A steel welding rod of low-carbon content
4
Fig. 95.
Pre-Heating Crankshaft with Gas
Burner
Fig. 96. Welding Crankshaft. Note that
the Pre-Heating Burner Is Used to
Assist the Welding Flame
should be used for filling material. No attempt should be made
to re-temper the spring, because the average garage is not equipped
to handle work of that nature and, consequently, the spring is very
Fig. 97. Welded Crankshaft
likely to be worse if a poor job of tempering is done than if tempering
is not attempted. It is well to pack wet asbestos around the spring
next to the weld to prevent the heat being conducted back into the
rest of the spring.
OXY-ACETYLENE WELDING
93
Shafts and Axles. Shafts and axles are alloys of nickel, nickel
and chromium, or chromium and vanadium. It is desirable to have
the filling material of the same composition as the shaft or axle,
but this is practically impossible. The most suitable welding rod
Fig. 98. Broken Malleable-Iron Rear-Axle Housing
that can be obtained for this work is one containing about 3.50
per cent nickel, or one containing about 0.20 per cent vanadium and
0.12 per cent chromium. This latter steel is more difficult to handle
under the welding flame, so that most welders prefer the 3.50 per
cent nickel rod.
Square shafts, Figs. 92 and 93, and round shafts, Fig. 80, page
76, should both be beveled by means of the cutting blowpipe or by
grinding, and should then be placed in alignment or in suitable
jigs, Fig. 94. A gas or oil pre-heating burner should then be directed
Fig. 99. Repaired Malleable-Iron Rear-Axle Housing
on the point of welding, Fig. 95, and the work heated to a red heat
before welding is started. The welding should then be carried on,
Fig. 96, according to the instructions given under Welding Heavy
Sections, page 58. After the welding has been completed the work
should be reheated and any straightening done that is necessary.
94
OXY-ACETYLENE WELDING
The weld should then be heated up evenly, covered over with sheet
asbestos, and allowed to cool slowly. The finished weld is shown
in Fig. 97.
Axle Housings. If the housing is of pressed steel, it will not
present any particular difficulty to the welder, except that he will
have to take care that it does not get out of alignment. A pure iron
welding wire should be used, and the work should be prepared and
carried on as explained under Light Sheet-Steel Welding, pages
46 to 50
If the housing is of malleable iron, Figs. 98 and 99, it should
be beveled, placed in alignment, and then brazed, using Tobin bronze
for a filling material as
explained under Malle-
able-Iron Welding, page
67. The work may be
pre-heated slightly to re-
lieve the effect of expan-
sion and contraction, but
must not be heated above a
dark red. The operator
must be very careful to
not bring the malleable
iron at the weld to too
high a heat or its mal-
leable properties will be
destroyed and the hous-
ing will be weak.
Manifolds. Pressed-
steel manifolds should be
Fig. 100. Welding Broken Flange on Manifold welded according to the
directions given under Light Sheet-Steel Welding, pages 46 to 50.
Cast-iron manifolds, as a rule, have only simple breaks to be
repaired, such as broken flanges, Fig. 100. These should be beveled,
and the parts clamped to a flat surface to keep them straight. They
should then be pre-heated in the vicinity of the weld by means of
the welding blowpipe before the welding is started. After the weld
is completed they should be reheated evenly and then covered
over and allowed to cool slowly.
OXY-ACETYLENE WELDING
95
Engine Cylinders. If the water jacket is cracked, the crack
should be chipped out and the surface of the casting next to the
groove should be cleaned by scraping. If the cylinder is cracked in
Fig. 101. Water Jacket Cut Away to Allow for Welding Cylinder Wall
the head end, it will be necessary to cut away a section of the water
jacket by drilling or sawing, Fig. 101. After the cylinder head has
been welded, the water-jacket section can be welded back into place,
Fig. 102. Sometimes it is quite difficult to detect how far the crack
really extends, therefore, care must be taken to be sure that it is
chipped out its entire length.
All of the plugs and other fittings must be removed from the
cylinders before pre-heating. The cylinders should be placed in
Fig. 102. Cylinder Wall Welded and Section of Water-Jacket Replaced
the pre-heating fire with the open end of the cylinder upward,
Fig. 103. They may be placed on a slant if the crack is on the side
of the water jacket; but they must be in such a position so there
96
OXY-ACETYLENE WELDING
will be no chance for dead air to remain in them. If this precaution
is not taken, the cylinder walls are very likely to crack.
The welding should be carried on according to the directions
given under Cast-iron Welding, pages 59 to 67. The cylinders
must be left in the charcoal fire all during the welding. It is even
advisable to keep the top of the fire covered over and to weld through
a hole in the asbestos paper, Fig. 103, to prevent air currents from
striking the cylinder while it is hot. After the welding has been
Fig. 103. Welding Cylinders and Preparing Pre-Heating Fire for Cylinders
completed, the fire should be started up enough to heat the entire
casting evenly, and should then be covered over and allowed to die
out. The cylinder must not be removed until it has become cold
enough to be handled with bare hands.
Protection for Machined Surfaces. The finish in the bore of the
cylinder will be affected by the heating if some means is not used
to protect it. The best protection that can be used is to coat it and
other machined surfaces with flaked graphite and oil. This can
be made into a paste and painted on, or the surfaces can be oiled
OXY-ACETYLENE WELDING
97
Fig. 104. Water Jacket Plugged and Welds Being Tested
Gasoline
with
and the graphite dusted on. The latter method is really the best
if carefully applied. The graphite must be coarse; the fine flake
will not do.
Testing Welded Cyl-
inders. There are sev-
eral ways of testing
welded cylinders. The
two most generally used
are by water pressure
and by gasoline. In the
first method, the water
jacket is tightly plugged,
filled with water, and
then subjected to pres-
sure by means of a hand
pump. The method of
using gasoline is simpler
and quicker. The water
jacket is plugged and
filled with gasoline, Fig.
104. If there are any
cracks or leaks the gas-
oline will work its way
through and will spread
out over the surface sur-
rounding the crack or
leak.
Crankcases and
Transmission Cases. It
is usually necessary to
remove the case from the
car. But, if the arm is
broken some distance
from the main case, it
may be welded while in
position, as shown in Fig. 105. When welding in this manner, it is
necessary to cover the parts near the welding with asbestos sheets
to protect them from the flame of the blowpipe. The arm should be
Fig. 105. Welding Arm of Crankcase without Dismantling
OXY-ACETYLENE WELDING
pre-heated slightly by means of the welding blowpipe before the
actual welding is started, and, after the welding has been completed,
it should be reheated to relieve
any internal strains, and must
then be covered over to allow it
to cool slowly.
Some operators spend a great
deal of time trying to keep the
bearing of the case in line, and
while doing this they allow the
rest of the case to twist, so that
it is necessary to take a machine
cut off the edges in order that
they may fit the other half of the
case. It is much better to keep
the edges true and dress up the
bearings, because it is quite likely that the bearings will have to be
trued up anyway. The case should be clamped flat against two
straightedges, but not too tight, or the case might crack from the
strains produced when heat is
applied. The case should be
placed on the welding table in
suchva position that the welder
can work on the outside and
smooth off the inside without
having to disturb its position.
The most satisfactory
method of pre-heating is to place
Fig. 106. Badly Broken Transmission Case —
Must Be Pre-Heated All Over
Fig. 107. Lower Half of Crankcase with Piece
Broken Out — Must Be Entirely Pre-Heated
Fig. 108. Upper Half of Crankcase with Piece Broken Out and Missing
a gas burner under the case and let it burn without an air blast. If an
air blast is turned on, the case is liable to become overheated and
OXY-ACETYLENE WELDING
99
cave in. In fact, unless there are holes to allow some of the heat
to escape, the case is liable to become overheated with only the
soft gas flame. If the case is broken at one end, as shown in Fig. 108,
it is only necessary to heat the one end; but it is very necessary to
heat both sides of that end to prevent warping. If like the case
shown in Figs. 106 or 107, it is best to heat the entire case. This
can best be done by using two gas burners so that the heat will
surely spread.
If the case is cracked or a piece is broken off, the welding should
start at the inner end of the crack and move toward the edge or corner.
The welding should be carried on
as directed under Cast Aluminum
Welding, page 71.
If a piece has been broken
out and lost necessitating building
Fig. 109. Sheet-Iron Form to Back Up Section to Be Welded-In
up a section of the casting, Fig. 108, it is necessary to back-up the
work by means of a piece of sheet iron bent to the required shape,
Fig. 109. The welding should be started at one edge and should
move across the space in a line parallel to the edge. When the
added material gets almost to the opposite edge, the welding should
stop, the edge of the case and the edge of the new added section
should be cleaned, and then the weld completed in the same manner
as for welding up a crack, Fig. 110, as outlined above.
COSTS
The cost of welding varies within wide limits for the different
metals and the different classes of work. It is, therefore, not possible
to give cost tables that will apply to all work. The costs given in
Tables II and III are for steel work under fair conditions.
Measuring Oxygen Consumption. Oxygen is supplied
compressed to 1800 pounds per square inch, in cylinders containing
100
OXY-ACETYLENE WELDING
TABLE II
Welding Cost Table
Thickness
of Metal
(in.)
Speed
(ft. per hr.)
Oxygen
per Linear Foot
(cu. ft.)
Acetylene
per Linear Foot
(cu. ft.)
Cost
per Linear Foot
Labor 45c
Oxygen. . . . 2c
Acetylene. . 2Jc
<&
26
0.15
0.14
$ .024
A
22
0.22
0.21
.030
&
17
0.43
0.41
.045
h
14
0.68
0.65
.063
i
Hi
1.03
0.98
.083
A
9
1.84
1.74
.13
1
7
3.01
2.88
.20
f
4|
6.74
6.44
.40
i
3
13.2
12.5
.73
I
H
38.7
37.0
2.00
i
l
76.7
72.9
3.81
TABLE III
Cutting Cost Table
Cost
Thickness
of Metal
(in.)
Speed
(ft. per hr.)
Oxygen
per Linear Foot
(cu. ft.)
Acetylene
per Linear Foot
(cu. ft.)
per Linear Foot
Labor 45c
Oxygen .... 2c
Acetylene.. 2jc
i
90
0.34
0.10
$ .014
i
74
0.55
0.17
.021
*
55
1.16
0.33
.040
a.
4
46
1.91
0.47
.060
1
40
2.75
0.61
.082
i*
33
4.70
0.85
.13
2
29
6.97
1.06
.18
3
24
12.3
1.46
.30
4
20
19.4
1.96
.46
6
15
38.3
3.04
.87
8
11
69.7
4.60
1.55
TABLE IV
Factors for Correcting Oxygen Volumes
Deg. F.
Factor
Deg. F.
Factor
Deg. F.
Factor
100
0.929
75
0.972
50
1.020
95
0.937
70
0.981
45
1.030
90
0.946
65
0.990
40
1.040
85
0.954
60
1.000
35
1.051
80'
0.963
55
1.010
30
1.061
101
OX Y- ACETYLENE WKLD-JNti
100 and 200 cubic feet. The amount pf oxygen im a; tyHafe^
be measured quite accurately by means of the high-pressure gage
on the regulator. Most of these gages are supplied with two rows
Fig. 110. Upper Half of Crankcase with Section Built-in
of figures on the dial, Fig. 111. The outer circle gives the pressure
in the cylinder in pounds per square inch, and the other circle gives
the per cent of oxygen remaining in the cylinder. The latter set of
numbers makes the calculation very easy: e.g., if a 100-cubic foot
cylinder is being used and the gage hand indicates 73, there is 73
ACETYLENE CO.
UVU50-NEWYORK
Fig. 111. Dial of High-Pressure Gage of Oxygen Regulator
cubic feet of oxygen in the cylinder. If a 200-cubic foot cylinder is
being used, there is 200X0.73 = 146 cubic feet in the cylinder.
The amount of oxygen indicated by the gage reading is more or less
approximate and depends upon the temperature of the oxygen in the
102 OXY-ACETYLENE WELDING
cylinder. The correction factors given in Table IV should be used
to determine the volume of the oxygen at "standard temperature",
60° F., if an accurate measurement is required, e.g., if in the case
given above the temperature is 50° F., then the real volume at
standard temperature would be 146X1.020 = 148.9 cubic feet.
Measuring Acetylene Consumption. The amount of acetylene
in a cylinder cannot be determined by means of the high-pressure
gage. All the high-pressure gage can be used 'for, in the case of
acetylene, is to indicate very roughly the amount of acetylene in
the cylinder. There is only one method that can be used to determine
the amount of acetylene used, and that is to weigh the cylinder.
Each pound by weight of acetylene is equal to 14.5 cubic feet. There-
fore, to determine the amount of acetylene used on a certain job, it is
necessary to weigh the cylinder before and after welding and
calculate the volume of acetylene used from the difference in weight,
e.g., if the cylinder weighs 217 pounds before welding and 207 J
pounds after welding, then (217 -207|)X 1.4.5 = 9JX 14.5 = 137.7
cubic feet.
INDEX
INDEX
PAGE
Acetylene 4
consumption 102
cylinders 4
generators 5
Adhesion 33
After-treatment 45, 66, 70, 72, 74, 76
Aluminum welding 68
cast 71
sheet 69
Annealing 45
Automobile repair, examples 87
axle housings 94
bodies and fenders 89
crankcases and transmission cases 97
engine cylinders 95
frames 87
manifolds 94
pressed-steel parts 87
shafts and axles 93
springs 92
B
Back-firing 24
Blowholes 66
Blowpipe : 7, 16
how to light 23
how to shut off 23
inclination 27
injector 7
manipulation 28, 44, 63
position 27
pressure 7
Brass welding 74
Bronze welding 74
Butt weld . 49, 54
C
Carbon removing by use of oxygen 85
Carbon blocks 67
Cast-iron welding 59
Charcoal fire 43
Connecting apparatus, instructions f or , , 22
INDEX
PAGE
Copper welding 72
Corner welds 50, 54
Costs 99
Cutting 10, 76
apparatus 78
principle • 77
Cylinder welding 49, 54
D
Defects in welds 32
E
Electric welding 11
apparatus 13
arc welder 12
spot-welder 11
Expansion and contraction 8, 36, 43, 46, 53, 58, 60, 68
complex case 39
methods of handling 37
simple case 37
F
Flange weld 49
Flux 9, 61, 69, 73, 75
G
Generators 5
low-pressure 5
pressure 6
Graphite electrode 13
H
Hammering 9, 46, 59
Holes, welding up 31
Hose.. . 21
Jigs 47
Lead burning 81
apparatus 83
M
Malleable-iron welding 67
Metallic electrode 13
Metals, properties of 34
INDEX
O PAGE
Overhead welding ..................................................... 31
Oxidation ............................................. 32, 43, 59, 68, 72, 74
Oxy-acetylene flame ..................................... 8, 24, 44, 69, 73, 75
Oxy-acetylene process ....................... ' .......................... 3
advantages ...................................................... 3
Oxygen .............................................................. 3
consumption ..................................................... 99
P
Penetration ......................... .................................. 33
Pipe welding ......................................................... 56
Pre-heating ..................................................... 40, 60, 71
methods ......................................................... 41
reasons .......................................................... 40
Preparation of work for welding ................ 8, 14, 46, 51, 57, 62, 71, 73, 75
Regulators ........................................................... 19
acetylene ........................................................ 20
care ............................................................. 21
cutting ..... -. ................................ .................... 79
operation ............................. ........................... 19
oxygen welding ................................................... 20
Reinforcing welds ............................ ......................... 34
Re-welding ..................................................... 70, 74, 76
Rods .......... . ................................... 8, 29, 44, 60, 68, 72, 75
S
Spot-welder .......................................................... 11
Steel welding ....................... . ................................. 43
castings. .... .................................................... 57
f orgings ......................................................... 57
heavy sheet ...................................................... 51
light sheet ....................................................... 46
Strength of welds ..................................................... 9
T
Tables
cutting cost table ............ ..................................... 100
factors for correcting oxygen volumes ................................ 100
properties of metals ............................................... 35
welding cost table ........................ ......................... 100
Tacking ............................................................. 47
Tank welding ................................................... 51, 55; 56
Tube welding ...................................................... 51, 56
V
Vertical welding ...................................................... 31
INDEX
W PAGE
Welding 15
brass 75
bronze 75
cast aluminum 71
cast-iron 63
copper 73
heavy sheet-steel 53
light sheet-steel , 48
malleable-iron 68
sheet-aluminum 70
steel castings 58
steel f orgings 58
Welding processes 1, 63
electric 11
old and new methods 1
oxy-acetylene 3
LD21-100m-7,'33
YC 13848
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